Parameter incompatibilities: Increase flexibility in incompatibilities handles.

[VGPReys]

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Refactor the way incompatible parameters are handled and written.
Hopefully allows for more flexibility and usage outside of the global parameters.

• more flexible: multiple incompatible parameters can be set for the same parameter
• can be used in other modules: when validating modules parameters, incompatible ones are also checked !

Closes #986

How to write an incompatible parameter ?

parameter1:
  default: "value1_X"
  incompatible:
    value1_X:
      parameter2: "value2_Y"
    value1_Y:
      parameter2: "value2_X"
parameter2:
  default: "value2_X"

How to read / write / understand it ?

parameter1 has an incompatibility when its value is value1_X with parameter2=value_Y.
Also, if parameter1 is taking the value value1_Y, parameter2 cannot be set to value2_X.

In this case, the default configuration file is fine, as parameter2 is having value2_X.

But if the user is putting value2_Y for parameter2, an error is thrown !

[rvhonorato]

Held by #987

better implementation of #987

The base branch was changed.