Add Red Hat 9.4 with non-blocking tests in CI

RHEL-9.4 will be run in parallel with RHEL-9.2 with insignificant tests
until RHEL-9.4 is confirmed stable, then it will replace RHEL-9.2.
[CI Platforms]

Adapted for 6.8:
* remove install-firebird.sh, which is only in dev
* remove 90-install-oracle.sh, which is only in dev

Task-number: QTQAINFRA-6362
Change-Id: I92c10a15346e7bd0c0190a8d6a6513cf6143d2a8
(cherry picked from commit ee8ee93d91)
Reviewed-by: Tim Blechmann <tim.blechmann@qt.io>

coin/platform_configs/qmake2cmake.yaml

@@ -13,6 +13,10 @@ Configurations:
     Template: 'qtci-linux-RHEL-9.2-x86_64-51'
     Compiler: 'GCC'
     Features: ['DisableTests']
+-
+    Template: 'qtci-linux-RHEL-9.4-x86_64-50'
+    Compiler: 'GCC'
+    Features: ['DisableTests']
 -
     Template: 'qtci-linux-Ubuntu-22.04-x86_64-51'
     Compiler: 'GCC'