Add role icinga2adm_r to SELinux policies

[htriem]

By default, newly-created files and directories inherit the SELinux type of their parent directories. This is how we've been doing things for a while now, but behaviour seems to have changed for some systems.
So it is required for role icinga2adm_r, setting the role to our SELinux admin level role, to be called before calling userdom_unpriv_user_template(icinga2adm) to allow for proper role and domain creation.
I've tested this on RHEL 9:

# semanage boolean -l | grep icinga
httpd_can_connect_icinga2_api  (on   ,   on)  Allow httpd to can connect icinga2 api
httpd_can_write_icinga2_command (on   ,   on)  Allow httpd to can write icinga2 command
icinga2_can_connect_all        (off  ,  off)  Allow icinga2 to can connect all
icinga2_run_sudo               (off  ,  off)  Allow icinga2 to run sudo
icinga2adm_exec_content        (on   ,   on)  Allow icinga2adm to exec content

Without this fix, this command doesn't print anything.

See Issue icinga-packaging/#276 for more info.

[htriem]

This PR now includes a fix for this issue in the second commit.

Disregard that, the fix for this issue has been moved to here.