Handling of low disk space

[jonherrmann]

in Status View

[jonherrmann]

First considerations:

• Warn user on low disk space in Status View
• Do not execute disk space intensive operations when disk space is low (implies prediction of disk space consumption) and notify user, see https://github.com/interactive-instruments/etf-webapp/issues/119
• Delete old test object data (based on a max lifetime property) e.g. db index files
• Delete old test objects after a configured time

Unclear:

• Prediction of disk space consumption of parallel executed tasks (sync required)