Move NetworkManager-ci part to separate plan

Correct used git repo for NM CI

Use moved upstream to gitlab.

Make fmf a bit nicer.

Remove discover from script only

It breaks running the other plan this way.

Prepare inside the script

plans/nm.fmf

@@ -0,0 +1,11 @@
+summary: Run Network Manager tests
+prepare:
+  how: install
+  packages: git-core
+execute:
+  how: tmt
+  script: |
+    dnf install -y git-core
+    git clone https://gitlab.freedesktop.org/NetworkManager/NetworkManager-ci.git
+    cd NetworkManager-ci
+    ./run/osci/run-tests dnsmasq

plans/tier1-public.fmf

@@ -1,17 +1,8 @@
-summary: Combine all availabe tests for dnsmasq
+summary: Combine all availabe beakerlib tests for dnsmasq
 discover:
   - name: fedora_tests_dnsmasq
     how: fmf
     url: https://src.fedoraproject.org/tests/dnsmasq.git
     filter: 'tier: 1'
-  - name: github_NetworkManager
-    prepare:
-      how: install
-      packages: git
-    execute:
-      script: |
-        git clone https://github.com/NetworkManager/NetworkManager-ci
-        cd NetworkManager-ci
-        ./run/osci/run-tests dnsmasq
 execute:
     how: tmt