Merge branch '61376-add-documentation-about-how-to-enable-puma-web-server-for-installations-from-source' into 'master'

Add documentation about how to enable Puma web server for installations from source

Closes #61376

See merge request gitlab-org/gitlab-ce!28235

(cherry picked from commit 5ec40522)

c06dfd9d Replace Unicorn with web server in the init.d script [ci skip]
95afca31 Add puma example for production [ci skip]
f2c6bfbe Add using Puma section to install from source [ci skip]
5ebf0492 Add Puma web server support to init.d file
aa7b053c Minor doc improvements to Puma instructions
29e49b45 Apply suggestion to doc/install/installation.md
6a691fa7 Apply suggestion to doc/install/installation.md