Add dev environment installation instructions for Arch Linux-based systems (#5192)

* Add installation instructions for Arch Linux-based systems

site/content/en/docs/contributing/development-environment.md

@@ -27,6 +27,28 @@ description: 'Installing a development environment for different operating syste
   brew install git python pyenv redis curl openssl node sqlite3 geos
   ```
 
+  Arch Linux
+  ```bash
+  # Update the system and AUR (you can use any other AUR helper of choice) first:
+  sudo pacman -Syyu
+  pikaur -Syu
+  ```
+
+  ```bash
+  # Install the required dependencies:
+  sudo pacman -S base-devel curl git redis cmake gcc python python-pip tk libldap libsasl pkgconf ffmpeg geos openldap python-lda
+  ```
+
+  ```bash
+  # CVAT supports only Python 3.9, so install it if you don’t have it:
+  pikaur -S python39
+  ```
+
+  ```bash
+  # Install Node.js 16, yarn and npm
+  sudo pacman -S nodejs-lts-gallium yarn npm
+  ```
+
 - Install Chrome
 
 - Install FFmpeg libraries (libav\*) version 4.0 or higher.
@@ -103,6 +125,17 @@ description: 'Installing a development environment for different operating syste
   > Change `tensorflow` to `tensorflow-macos`
   > May need to downgrade version Python to 3.9.* or upgrade version `tensorflow-macos`
 
+  > Note for Arch Linux users:
+  >
+  > In order to build `python-ldap`, the `gcc` compiler needs to be pointed to the right file, since lib name has been changed from `libldap_r` to `libldap`, otherwise wheels for `python-ldap` won't be built and the install will fail. You need to create a symlink between the newer and older `ldap` libraries:
+  > ```
+  > sudo ln -s /usr/lib/libldap.so /usr/lib/libldap_r.so
+  > ```
+  >
+  > Because PyAV as of version 10.0.0 already [works](https://github.com/PyAV-Org/PyAV/pull/910) with FFMPEG5, you may consider changing the `av` version requirement in `/cvat/cvat/requirements/base.txt` to 10.0.0 or higher.
+  >
+  > Perform these actions before installing cvat requirements from the list mentioned above.
+
 - Create a super user for CVAT:
 
   ```bash
@@ -182,3 +215,10 @@ You develop CVAT under WSL (Windows subsystem for Linux) following next steps.
 
 - You might have to manually start the redis server. You can do this with `redis-server`.
 Alternatively you can also use a redis docker image instead of using the redis-server locally.
+
+## Note for Arch Linux users
+- You need to start `redis` and `docker` services manually in order to begin debugging/running tests:
+  ```bash
+  sudo systemctl start redis.service
+  sudo systemctl start docker.service
+  ```