Add Cargo package registry (#21888)

This PR implements a [Cargo registry](https://doc.rust-lang.org/cargo/)
to manage Rust packages. This package type was a little bit more
complicated because Cargo needs an additional Git repository to store
its package index.

Screenshots:

![grafik](https://user-images.githubusercontent.com/1666336/203102004-08d812ac-c066-4969-9bda-2fed818554eb.png)

![grafik](https://user-images.githubusercontent.com/1666336/203102141-d9970f14-dca6-4174-b17a-50ba1bd79087.png)

![grafik](https://user-images.githubusercontent.com/1666336/203102244-dc05743b-78b6-4d97-998e-ef76341a978f.png)

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

doc/advanced/config-cheat-sheet.en-us.md

@@ -1213,6 +1213,7 @@ Task queue configuration has been moved to `queue.task`. However, the below conf
 - `CHUNKED_UPLOAD_PATH`: **tmp/package-upload**: Path for chunked uploads. Defaults to `APP_DATA_PATH` + `tmp/package-upload`
 - `LIMIT_TOTAL_OWNER_COUNT`: **-1**: Maximum count of package versions a single owner can have (`-1` means no limits)
 - `LIMIT_TOTAL_OWNER_SIZE`: **-1**: Maximum size of packages a single owner can use (`-1` means no limits, format `1000`, `1 MB`, `1 GiB`)
+- `LIMIT_SIZE_CARGO`: **-1**: Maximum size of a Cargo upload (`-1` means no limits, format `1000`, `1 MB`, `1 GiB`)
 - `LIMIT_SIZE_COMPOSER`: **-1**: Maximum size of a Composer upload (`-1` means no limits, format `1000`, `1 MB`, `1 GiB`)
 - `LIMIT_SIZE_CONAN`: **-1**: Maximum size of a Conan upload (`-1` means no limits, format `1000`, `1 MB`, `1 GiB`)
 - `LIMIT_SIZE_CONDA`: **-1**: Maximum size of a Conda upload (`-1` means no limits, format `1000`, `1 MB`, `1 GiB`)

doc/packages/cargo.en-us.md

@@ -0,0 +1,109 @@
+---
+date: "2022-11-20T00:00:00+00:00"
+title: "Cargo Packages Repository"
+slug: "packages/cargo"
+draft: false
+toc: false
+menu:
+  sidebar:
+    parent: "packages"
+    name: "Cargo"
+    weight: 5
+    identifier: "cargo"
+---
+
+# Cargo Packages Repository
+
+Publish [Cargo](https://doc.rust-lang.org/stable/cargo/) packages for your user or organization.
+
+**Table of Contents**
+
+{{< toc >}}
+
+## Requirements
+
+To work with the Cargo package registry, you need [Rust and Cargo](https://www.rust-lang.org/tools/install).
+
+Cargo stores informations about the available packages in a package index stored in a git repository.
+This repository is needed to work with the registry.
+The following section describes how to create it.
+
+## Index Repository
+
+Cargo stores informations about the available packages in a package index stored in a git repository.
+In Gitea this repository has the special name `_cargo-index`.
+After a package was uploaded, its metadata is automatically written to the index.
+The content of this repository should not be manually modified.
+
+The user or organization package settings page allows to create the index repository along with the configuration file.
+If needed this action will rewrite the configuration file.
+This can be useful if for example the Gitea instance domain was changed.
+
+If the case arises where the packages stored in Gitea and the information in the index repository are out of sync, the settings page allows to rebuild the index repository.
+This action iterates all packages in the registry and writes their information to the index.
+If there are lot of packages this process may take some time.
+
+## Configuring the package registry
+
+To register the package registry the Cargo configuration must be updated.
+Add the following text to the configuration file located in the current users home directory (for example `~/.cargo/config.toml`):
+
+```
+[registry]
+default = "gitea"
+
+[registries.gitea]
+index = "https://gitea.example.com/{owner}/_cargo-index.git"
+
+[net]
+git-fetch-with-cli = true
+```
+
+| Parameter | Description |
+| --------- | ----------- |
+| `owner`   | The owner of the package. |
+
+If the registry is private or you want to publish new packages, you have to configure your credentials.
+Add the credentials section to the credentials file located in the current users home directory (for example `~/.cargo/credentials.toml`):
+
+```
+[registries.gitea]
+token = "Bearer {token}"
+```
+
+| Parameter | Description |
+| --------- | ----------- |
+| `token`   | Your [personal access token]({{< relref "doc/developers/api-usage.en-us.md#authentication" >}}) |
+
+## Publish a package
+
+Publish a package by running the following command in your project:
+
+```shell
+cargo publish
+```
+
+You cannot publish a package if a package of the same name and version already exists. You must delete the existing package first.
+
+## Install a package
+
+To install a package from the package registry, execute the following command:
+
+```shell
+cargo add {package_name}
+```
+
+| Parameter      | Description |
+| -------------- | ----------- |
+| `package_name` | The package name. |
+
+## Supported commands
+
+```
+cargo publish
+cargo add
+cargo install
+cargo yank
+cargo unyank
+cargo search
+```

doc/packages/overview.en-us.md

@@ -26,6 +26,7 @@ The following package managers are currently supported:
 
 | Name | Language | Package client |
 | ---- | -------- | -------------- |
+| [Cargo]({{< relref "doc/packages/cargo.en-us.md" >}}) | Rust | `cargo` |
 | [Composer]({{< relref "doc/packages/composer.en-us.md" >}}) | PHP | `composer` |
 | [Conan]({{< relref "doc/packages/conan.en-us.md" >}}) | C++ | `conan` |
 | [Conda]({{< relref "doc/packages/conda.en-us.md" >}}) | - | `conda` |