Add warning not implemented for all tests

[karacolada]

Actions:

• [x] add general metric definitions to YAML
• [x] add CESSDA-specific metric definitions to YAML
• [x] identify the relevant evaluators and register FRSM metric with them
• [x] identify the relevant test functions, register FRSM metrics with them, add new test functions with warning if necessary
• [x] add necessary evaluators and their test functions with with a "not implemented" warning message
• [x] for all new evaluators: add necessary new output types, or is there a generic one we can use for now?

[karacolada]

Note that FRSM 6, 15, 16, 17 are assigned to evaluators that cater more than one FRSM. I'm not sure this works, so keep in mind for the test function registrations

[karacolada]

All actions complete. Metrics are now all listed, with "NotImplemented" warnings in the debug messages where appropriate. Seems to all be working.