Add feature to allow execution of single functional test

[agrojean-ledger]

The feature should maybe use Pytest's --collect-only option to detect all available tests and populate a list from which the user can pick one or several tests (which check boxes ?)

[tdejoigny-ledger]

applicable for all run tests actions + generate golden snapshots

[tdejoigny-ledger]

to generalize, we could even merge the test actions with for example:

click on run test
and then we have these choices
test name/all tests ----- display (true/false) ----- on device (true/false) ----golden snapshots (true/false)

Wdyt @agrojean-ledger ? is it feasible in term of UI ?

cc: @cedelavergne-ledger