Better automatic handling and checking of variable declarations

[mlange05]

Is your feature request related to a problem? Please describe.

The current sanity checking and housekeeping for variable and argument declarations is hidden behind property setters and assumes that the given list is complete.

Describe the solution you'd like

A additional convenience API that can add/remove/ensure consistent declarations exist for a list of type symbols would make this more user friendly and would allow for some simplification and removal of redundant code paths in various transformations and pipelines.

Describe alternatives you've considered

No response

Additional context

No response

Organisation

ECMWF