Stop using InitDb in tests

[andchiind]

Describe the improvement you would like to see
We are still using values from initDb when running our unit tests, in particular robot models. This can be quite annoying as changing initDb is useful for performing manual tests and it is not obvious which values are expected in the unit tests. It is for instance expected that we do not use the battery or pressure range limits, otherwise the tests in MissionTests fail. It is better in my opinion to only use data records created in mocks and utility functions within the testing folder.

How will this change existing functionality?
It will better separate the tests from the rest of the project files and it will make it more clear where the values being tested are defined.

How will this improvement affect the current Threat Model?
N/A