Deprecate Inputs.connect and handle ambiguous connections

[PProfizi]

The current Inputs.connect method tries to connect an object to an input pin accepting the object type.
This worked when only one input accepted a certain type, and raised an error about ambiguity when several were available.
This effectively prevents from having operators with two inputs accepting a same type.

This PR changes the current behavior in two ways:

• it allows for operators with two inputs accepting a same type to use this method to ensure retro-compatibility of scripts, and it picks the first input found accepting the type, raising a warning instead of an errror.
• it marks the Inputs.connect method as deprecated in favor of explicit output-to-input connections.

[codecov]

Codecov Report

Attention: Patch coverage is 20.00000% with 8 lines in your changes missing coverage. Please review.

Project coverage is 88.53%. Comparing base (b673c4f) to head (17c5ad3).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2053      +/-   ##
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- Coverage   88.55%   88.53%   -0.03%     
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  Files          90       90              
  Lines       10225    10231       +6     
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+ Hits         9055     9058       +3     
- Misses       1170     1173       +3