First-Tier contribution analysis tab

[marc-vdm]

@mrvisscher This PR is ready for testing by other people, based on more testing I hope we can remove some potential bugs and merge this.

New feature to implement contribution analysis for products.

• Resolves 1st level contributions #810
• Resolves Show contributions of all activities/biosphere flows of production activity #572
• Resolves Results of the single technosphere elements of an activity #1005

Add:

• CA data: use actual total instead of sum(abs)
  • here
• CA data: make distinction between positive and negative rest values (resolve Contribution graphs > Rest should be split into positive and negative sections #886)
  • here
• CA data: sort based on average of row instead of first column (resolve Sorting Contribution Analysis tables better #887)
  • here
• CA table: consistent dropping of empty (rest) rows (resolve Contribution analysis rest row sometimes doesn't show in table + index missing #1044)
  • here
• CA figure: add marker to show total score when both positive and negative results present (resolve Figure improvements 4/x - Contributions graphs with negative values #647)
  • here

Example project:
positive_negative_CA.tar.gz

Example:

Checklist

• Keep pull requests small so they can be easily reviewed.
• Update the documentation, please follow the numpy style guide
• Update tests.
• Categorize the PR by setting a good title and adding one of the labels:
  bug, feature, ui, change, documentation, breaking, ci
  as they show up in the changelog
• Link this PR to related issues.

[coveralls]

coverage: 53.511% (-0.7%) from 54.184%
when pulling a9ca09f on marc-vdm:first_level_cont
into 05bad41 on LCA-ActivityBrowser:main.