* fix(opensuse): update to openSUSE Leap >= 15.4

Signed-off-by: Georg Pfuetzenreuter <mail@georg-pfuetzenreuter.net>

* feat(opensuse): optional openSUSE devel repository

All modern openSUSE releases (Leap 15.x, Tumbleweed) ship nginx in the
default repositories. The devel repository should not be used unless the
user knows what they are doing.

Signed-off-by: Georg Pfuetzenreuter <mail@georg-pfuetzenreuter.net>

* fix(opensuse): pkgrepo.absent TypeError

Repository can only be removed by name, other fields cause del_repo() to
fail.

Signed-off-by: Georg Pfuetzenreuter <mail@georg-pfuetzenreuter.net>

---------

Signed-off-by: Georg Pfuetzenreuter <mail@georg-pfuetzenreuter.net>

Entries are being duplicated as described in

* https://github.com/saltstack/salt/issues/60220 and
* https://github.com/saltstack/salt/issues/59785#issuecomment-826590482

* correctly set dependencies in configuration
* update RPM repo key
* add tests for passenger installation as nginx module
* update test matrix

```bash
Examining nginx/pkg.sls of type state
[201] Trailing whitespace
nginx/pkg.sls:149
    - gpgcheck: 0
```

BREAKING CHANGE: all previous `nginx` based configurations must be reviewed;
`nginx.ng` usage must be promoted to `nginx` and any uses of the original
`nginx` will have to be converted.

Removed comment after testing that this change works with xenial

Build NGINX from source with nginx.ng state with support for passing
compile time flags necessary for installing modules such as more headers
by the openresty project.

On Ubuntu, you can take advantage of Personal Package Archives on Launchpad simply by specifying the user and archive name.  On other apt-based systems this must be the complete entry as it would be seen in the sources.list file.

* removed override releasever variable use for CentOS

Needed to add repo management because opensuse doesn't have nginx
in default repo