Integrate model reference in mock table

[Somtom]

Problem

The current API is still a bit verbose and unclear, for example:

• For all test cases we need to repetitively provide the table reference of the input data mocks. Usually those don't change.
• To generate results from mock input data we currently use a method called from_inputs. The feels seems a bit unclear (i.e. what is "inputs")?.
• When instantiating a class, we pass the data as list of dicts. However, there is also a from_inputs method. It can become unclear to the user what happens when

What changed

• Added a table_meta decorator that can be used to pass MockTable metadata (at the moment only table_ref - we will be able to reuse this in the future for other metadata). This way, we can leave the class attribute definition to only column types
• We renamed from_inputs to from_mocks
• We added a wrapper method from_dicts that should make more clear what happens compared to the new from_mocks method