[3.4] Update supported OSes (add Alma Linux, RPi OS 11, drop EOL OSes) (#5440) (#5496)

* Drop Fedora 33

By the time we release, it's going to reach EOL.

* Drop Raspberry Pi OS 10, add support for 11

* Bring RPi OS 10 back

* Add Alma Linux 8

* Fix-up RHEL EOL dates

* Add '(Legacy)' to Raspberry Pi OS 10

* Drop CentOS 8.
(cherry picked from commit d1df27bc14)

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

docs/install_guides/index.rst

@@ -13,9 +13,9 @@ we recommend **Ubuntu 20.04 LTS**.
 
    windows
    mac
+   alma-linux-8
    arch
    centos-7
-   centos-8
    centos-stream-8
    debian-10
    debian-11
@@ -24,6 +24,7 @@ we recommend **Ubuntu 20.04 LTS**.
    opensuse-tumbleweed
    oracle-linux-8
    raspberry-pi-os-10
+   raspberry-pi-os-11
    rhel-8
    rocky-linux-8
    ubuntu-1804