Replace TemporalProfileLayer instance

[jakimowb]

Temporal profile visualization in version <= 1.20 has several disadvantges:

• The ProfileViewDock uses a TemporalProfileLayer(QgsVectorLayer) reference. If garbage collected, this leads to runtime errors, like: Process finished with exit code -1073741819 (0xC0000005)
• temporal profile cannot be stored persistantly or used by other softer

The following improvements are requested:

• get rid of TemporalProfileLayer instance
• allow to save temporal profile in any vector layer
• store temporal profile data in JSON dumps
  • save all bands from all sensors in a multi-sensor time-series
  • save TP source sensor IDs
• asynchronuos loading of TP's, e.g. in QgsProcessingAlgorithms
  • Load for multiple points and time series sources
  • as QgsTask
  • as QgsProcessingAlgorithms
  • use multi-threading (load from n > 1 images in parallel)
• allow to reload TPs from other vector layers
• Revise TP Visualization Widget
  • implement plot settings as tree model (almost done, QStandardItemModel)
  • use PyQtGraph-like date axis (see DateAxisItem pyqtgraph/pyqtgraph#74)
  • show profile labels
  • show tooltip for TP data points with date, sensor, and other information
  • expressions to filter profiles (from potentially large vector layers with thousand of TPs) based on QgsFeature attributes
  • visualize TPs from different vector layers
• use Awesome Spectral Library (ASL) to provide shortcuts
  • add ASL to EOTSV code
  • implement QgsExpressionFunction to use ASL in QgsExpressionBuilder
  • short-cuts to calculate indice
  • use short-cuts to select predefined band-combinations (similar to EnMAP-Box)

[jakimowb]

State of TP Visualization widget: