remove "Band Properties" LayerConfigWidget; create a new standalone app that can actually edit the source

[Andreas Janz]

Discussed in team.

This way a Layer Property widget isn’t changing the layer source, which is unusual.

The new app should check if the source is already used by another QgsProject.mapLayers() layer. If so, ask the user to close it.

[Andreas Janz]

Make sure to also fix #943, by including functionality to get wavelength infos from the ENVI header, even if a GDAL *aux.xml file already exists.

[Andreas Janz]

Also implement: https://bitbucket.org/hu-geomatics/enmap-box/issues/938/read-reflectance-scale-factor-field-in-hdr

[Andreas Janz]

New GUI

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[Andreas Janz]

We now check whether the source is already owned by QGIS

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[Andreas Janz]

Uses the Edit raster source band properties algorithm to save properties to source, see #1010.

[Andreas Janz]

resolves #950 and #1010

→ <<cset c2df9ca52ea4>>