Remove support for opensuse

We haven't been testing the distro for a while in CI, e.g. in
Tempest, the jobs on opensuse15 haven't been executed for a year
now.
Therefore the patch removes opensuse support from devstack.

Closes-Bug: #2002900
Change-Id: I0f5e4c644e2d14d1b8bb5bc0096d1469febe5fcc

Author: kopecmartin

doc/source/index.rst

@@ -38,8 +38,7 @@ Install Linux
 
 Start with a clean and minimal install of a Linux system. DevStack
 attempts to support the two latest LTS releases of Ubuntu, the
-latest/current Fedora version, CentOS/RHEL/Rocky Linux 9, OpenSUSE and
-openEuler.
+latest/current Fedora version, CentOS/RHEL/Rocky Linux 9 and openEuler.
 
 If you do not have a preference, Ubuntu 22.04 (Jammy) is the
 most tested, and will probably go the smoothest.

doc/source/plugins.rst

@@ -243,9 +243,6 @@ locations in the top-level of the plugin repository:
 - ``./devstack/files/rpms/$plugin_name`` - Packages to install when running
   on Red Hat, Fedora, or CentOS.
 
-- ``./devstack/files/rpms-suse/$plugin_name`` - Packages to install when
-  running on SUSE Linux or openSUSE.
-
 Although there a no plans to remove this method of installing
 packages, plugins should consider it deprecated for ``bindep`` support
 described below.