add uncertanty of prediction

[luiskuhn]

• add the uncertainty maps in the reports (next to input img, and seg)
• add a column in the output "ratios" table of the report, summarising uncertainty per zone

[luiskuhn]

would be nice to have, low priority but we should work on that for the paper (I'll take this over once I am back, I already have an implementation)

[luiskuhn]

uncertainty maps added to dev, the request for new columns for "ratios" table is now a separate issue: https://github.com/qbic-pipelines/root-tissue-analysis/issues/26

[luiskuhn]

Solved by: https://github.com/qbic-pipelines/root-tissue-analysis/pull/21