Fix serialization and plotting jobs without loaded data

1. Instrument is a PolyPtr now. This fixes job deserialization.
2. Single-purpose signals like newJobFinished and updJobView are used instead of general-purpose signals to reduce excessive calling and to ease understanding signal chain.
3. Plot1DFrame and Plot2DFrame now have conditional subscriptions, depending on their context (data, sim or job) and react only on related events.
4. Some connections do require flag Qt::UniqueConnection. Otherwise the number of calls accumulates and grows over time.

requested review from @j.wuttke

assigned to @m.svechnikov

marked this merge request as ready

changed the description

approved this merge request

mentioned in commit 2b8d701f

merged