Optimise Squonk Job File Transfer

[alanbchristie]

(This feature was originally described in #944, which has now changes to focus on better Job configuration)

This issue concerns the following (originallly from #944): -

FE need to refactor job execution into a single request (2) [0, ?]
BE need to refactor job execution requests as a single process (2) [2, 0]

Notes:

Currently FE first makes request to copy files, then when that is complete, requests the job to execute. This need to change to be a single request for which the BE executes both aspects
Should also consider the impact of jobs using data from the RHS
Probably this involves the FE sending the "visit id", from which the BE can work out which Squonk project to use.

Current estimates for development (excludes deployment and testing):

BE days: 6.5
FE days: ?

[boriskovar-m2ms]

Basically we need to merge two dialogs into one. Should be around 2 days.

[alanbchristie]

This might be resolved by the work now scheduled for #1643 (Squonk Jobs from LHS download)?