create NodeNG.inferred_best() and replace inferred()[0]

[ostr00000]

Type of Changes

	Type
✓	✨ New feature
✓	🔨 Refactoring

Description

Add inferred_best function to NodeNG interface.
Replace all code where inferred()[0] is used.

Closes #2065

[codecov]

Codecov Report

Merging #2066 (282b75c) into main (598e4c3) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2066   +/-   ##
=======================================
  Coverage   92.82%   92.82%           
=======================================
  Files          95       95           
  Lines       11067    11069    +2     
=======================================
+ Hits        10273    10275    +2     
  Misses        794      794           

Flag	Coverage Δ
linux	92.59% <100.00%> (+<0.01%)	⬆️
pypy	88.17% <100.00%> (+<0.01%)	⬆️
windows	92.38% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
astroid/nodes/node_ng.py	93.11% <100.00%> (+0.04%)	⬆️

[ostr00000]

I am closing this, since code with inferred()[0] should be refactored another way (Ideally we would always check all results of infer() or use safe_infer to make sure we are using the "full" result and not [0] or [-1]).
See #2065 for more details.