Resolve "Make the Cache connection optional"

Closes #990 (closed)

added 42 commits

• 9b5b4ada...0985e888 - 41 commits from branch development
• 58f85ea1 - Merge branch 'development' into '990-make-the-cache-connection-optional'

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added 3 commits

• 55fc047a - Catching connection error to redis cache in middleware
• babf8e73 - Cache is now optional in every step of metager search
• 0b4fbc9d - added prometheus exporter to count successfull humanverifications

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unmarked as a Work In Progress

enabled an automatic merge when the pipeline for 0b4fbc9d succeeds

mentioned in commit 138438ae

merged