PLS: Add loadings to coefficients table

[VesnaT]

Issue

Alternative to #6780

Description of changes

• add loadings columns to Coefficients output
• rename Coefficients output to Coefficients and Loadings

Includes

• [X] Code changes
• [X] Tests
• [ ] Documentation

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 88.22%. Comparing base (d8818b5) to head (dfdc6b7). Report is 2 commits behind head on master.

:exclamation: Current head dfdc6b7 differs from pull request most recent head c7ca1b2. Consider uploading reports for the commit c7ca1b2 to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #6793 +/- ## ========================================== - Coverage 88.22% 88.22% -0.01% ========================================== Files 327 327 Lines 71273 71246 -27 ========================================== - Hits 62883 62855 -28 - Misses 8390 8391 +1 ```