Merge branch 'feature/refactor-selected-test-script' into 'master'

feature/refactor-test-selection

See merge request !2626

(cherry picked from commit d2606b8f)

a4d5cad8 [bin] add script to detect modified files
3e12917e [bin][findtests] pass changed file list as arg
135007f9 [bin][findtests] use more appropriate flag
f12a5240 avoid obsolete dunecontrol call
a4659d04 [ci] add merge request branch info output
fe78beb1 [ci] pass more mr-related variables downstream
7770fbfa [ci] remove default value for target branch
4b2b969c [ci] print trigger source var in job
65f3548b [ci] decide build/test job based on selection job result
9ecda465 [bin][getchangedfiles] prefer subprocess' cwd over chdir
ae76d3d3 [bin][findtests] make functions accept build-dir
b972895b [bin][findtests] avoid caching mechanism