Delete output files on re-run & UI run check

[ajstewart]

This fixes #418 and removes the parquet and arrow files before the run is re-run.

It also adds a check when running though the UI that the run is not already running or is queued (maybe an old tab is open or something).

For future reference, two things will need to changed:

• Files to not be deleted when Add the ability to 'add' an image to an existing job #212 is implemented.
• Arrow files deletion can be dropped when Remove arrow file generation when vaex 4.0.0 is available #405 is addressed.

[srggrs]

See my comment below

[ajstewart]

@srggrs the forced measurements parquet was a little confusing in the current state - as it stands, until we are able to add an image, and because we don't store the job running config in the DB, when re-running a pipeline the forced measurements should always be checked for and removed.

So I've removed the removal step in the actual forced extraction part of the code and made the removal of the old data in the run pipeline command take care of everything. It will check for the forced measurements to delete from the database on every re-run and delete all the parquets.

[srggrs]

All good! Merge master after merging #401 then I'll approve

[ajstewart]

All good! Merge master after merging #401 then I'll approve

@srggrs all merged.