Test Repository concurrency problems can lead to duplicated Tests in Test Plan board or Test Repository

Test Repository actions are not atomic/thread safe.

Through concurrent edit actions (rest or GUI), it is possible to reach invalid states.

e.g.: it is possible to move a test simultaneously to 2 different folders, as each concurrent action will be adding the test to a different folder without having to remove it from the other folder, leading to a state where the same test is placed in multiple folders within the same repository.

This should be fixable by making each action 'atomic' with a 'locking' strategy