[ENH] Select Rows: Allow partial context matches

[janezd]

Issue

Description of changes

Allow partial matches (but request matching at least one attribute) and remove non-matching conditions.

In case of multiple matches, take the match with the most matching variables.

Includes

• Code changes
• Tests

[codecov]

Codecov Report

Merging #4740 into master will increase coverage by 0.00%.
The diff coverage is 86.66%.

@@           Coverage Diff           @@
##           master    #4740   +/-   ##
=======================================
  Coverage   83.69%   83.70%           
=======================================
  Files         275      275           
  Lines       55620    55629    +9     
=======================================
+ Hits        46551    46562   +11     
+ Misses       9069     9067    -2     

[janezd]

This PR won't have >= 95 % diff coverage because conditions is the only context setting at the moment, so if setting.name != "conditions" can never be true, but it must remain there for the case we add some it in the future.