Move unit tests into tests/unit folder

[phil-davis]

The unit tests are currently directly inside the tests folder. Create tests/unit and move the unit tests there.

Related to owncloud/activity#1074 - the logic to decide if a unit test has changed depends on the unit tests being in a directory called tests/unit

[phil-davis]

Whoever does this, look at other oC10 app repos that have the unit tests in tests/unit and do the same.

And there are some apps that have the unit tests in tests/Unit (with an uppercase "U"). Change the to lowercase tests/unit to make everything consistent.

Tidy up phpunit.xml while doing this issue - make it as consistent as possible in each oC10 app repo.

[phil-davis]

@grgprarup FYI I edited my comment #198 (comment)

Please see how much we can make phunit.xml (and any other unit test scripts, settings etc) consistent in "every" oC10 app.

[SagarGi]

Covered up all the apps having drone star and having phpunit tests. So closing this issue.