MVP Create test runs based on change log

[isabelrios]

This is an MVP meant to share the progress on this new tool so that team members can experiment with it.

For now it is working only for iOS.
The way you can call it is by running the script:

python3 run_release_selection.py BASE HEAD
BASE: firefox-v147.4
HEAD: firefox-v147.5

This will give an output as:

Base tag: firefox-v147.4
Head tag: firefox-v147.5

Total changed files (raw): 202
After filtering ignored paths: 100
Unmatched files: 33
Impacted components: ['ab_testing', 'analytics', 'app_lifecycle', 'architecture', 'assets', 'browser_core', 'configuration', 'experiments', 'favicons', 'feature_flags', 'focus_browser', 'homepage', 'initialization', 'navigation', 'networking', 'onboarding', 'preferences', 'privacy', 'resources', 'rust_components', 'search', 'settings', 'shared_code', 'sync', 'tab_management', 'tabs', 'telemetry', 'toolbar', 'ui_components', 'utilities', 'voice_input', 'web_rendering']
Selected 1 test cases
Test run crated : Testrun ID

For example: https://mozilla.testrail.io/index.php?/runs/view/135534

Test runs are meant to be created within a Milestone, I'm using this one https://mozilla.testrail.io/index.php?/milestones/view/6652 which is in Test Project - Mobile