upstream CI: Simplify pipelines enviroment creation

Several optimizations have been done to the pipelines, to make them
closer to what can be reproduced, with the existing scripts, in a
development environment:

- Use start.sh and build.sh scripts to build and start containers
- Use variables to configure different stages instead of using separate
  files
- Use a commom 'prepare_environment' to create the environment for every
  pipeline
- Use a single file defining testing steps (run_tests.yml)
- Remove Centos 7 pipelines
- Reduce the number of pipelines in the test matrix due to the amount of
  time that tests were using
- Use Azure "loop" (each) to create test groups

The above changes make the pipelines easier to understand and modify.

infra/azure/pr-pipeline.yml

@@ -12,67 +12,58 @@ stages:
 - stage: Fedora_Latest
   dependsOn: []
   jobs:
-  - template: templates/fast_tests.yml
+  - template: templates/run_tests.yml
     parameters:
       build_number: $(Build.BuildNumber)
       distro: fedora-latest
       ansible_version: "-core >=2.15,<2.16"
+      skip_git_test: false
 
 # Galaxy on Fedora
 
 - stage: Galaxy_Fedora_Latest
   dependsOn: []
   jobs:
-  - template: templates/fast_tests.yml
+  - template: templates/run_tests.yml
     parameters:
       build_number: $(Build.BuildNumber)
       distro: fedora-latest
       ansible_version: "-core >=2.15,<2.16"
+      skip_git_test: false
+      test_galaxy: true
 
 # CentOS 9 Stream
 
 - stage: CentOS_9_Stream
   dependsOn: []
   jobs:
-  - template: templates/fast_tests.yml
+  - template: templates/run_tests.yml
     parameters:
       build_number: $(Build.BuildNumber)
       distro: c9s
       ansible_version: "-core >=2.15,<2.16"
+      skip_git_test: false
 
 # CentOS 8 Stream
 
 - stage: CentOS_8_Stream
   dependsOn: []
   jobs:
-  - template: templates/fast_tests.yml
+  - template: templates/run_tests.yml
     parameters:
       build_number: $(Build.BuildNumber)
       distro: c8s
       ansible_version: "-core >=2.15,<2.16"
-      target_python: "/usr/libexec/platform-python"
-
-# CentOS 7 cannot be used with current systemd
-#
-# CentOS 7
-#
-# - stage: CentOS_7
-#   dependsOn: []
-#   jobs:
-#   - template: templates/fast_tests.yml
-#     parameters:
-#       build_number: $(Build.BuildNumber)
-#       distro: centos-7
-#       ansible_version: "-core >=2.15,<2.16"
-#       target_python: "/usr/bin/python2"
+      skip_git_test: false
 
 # Rawhide
 
 - stage: Fedora_Rawhide
   dependsOn: []
   jobs:
-  - template: templates/fast_tests.yml
+  - template: templates/run_tests.yml
     parameters:
       build_number: $(Build.BuildNumber)
       distro: fedora-rawhide
       ansible_version: "-core >=2.15,<2.16"
+      skip_git_test: false