Remove (system card) mocks

[anneschuth]

• We remove all mocking from the AMT and move everything related to system_cards to the Project.system_card (serialized to the db)
  • Static System card from disk, for instance here: /amt/api/routes/project.py#L304
  • Fixed AI Act profile in project creation /amt/api/routes/projects.py#L125
• out of scope:
  • Model inference #309
  • Obtaining correct requirements/measures based on AI Act Profile
• We keep the file system storage abstractions around
• We may want to keep only the option to mock (through selecting a default template) when creating a project?
• out of scope is increasing the test coverage: Bring test coverage back #312

[uittenbroekrobbert]

For implementation of using the template when creating a new project; A hidden field is used instead of the option to select a template, as the latter would make things more complicated at this point. This is by request of @robbertbos