Simplify definition of counted parameters by computing them on the fly from definition.

[VGPReys]

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A solution to compute on the fly counted parameters, such as:

• nfle
• nncs (previously known as numncs)
• ncXsym (previously known as numcXsym)
• nsXsym (previously known as numsXsym)

Allows to remove one parameter from user configuration files.
Parameters are (and must still be) present in the defaults.yaml as hidden expertise level.

Related to #919
Closes #1029

[rvhonorato]

Check if this goes before, after or if it does not matter -> #969

[VGPReys]

Does not matter.
Could be merged before, as quite related.

[amjjbonvin]

Related to issue #919

[sverhoeven]

Tried it out in the workflow builder, in the preview looks much cleaner when guru catalog is selected, emref is node is added and symmetry fieldset is expanded.