Implement the Orientation Viewer in 5x

[smk78]

#1271 noted that the Orientation Viewer present in 4x needed to be implemented in 5x. However, until now, that requirement does not appear to have been ticketed.

[rozyczko]

Hmm we had the Orientation Viewer implemented at some point...

[rozyczko]

ah.

 # orientation viewer set to invisible SASVIEW-1132
 self._workspace.actionOrientation_Viewer.setVisible(False)

this points to the bug report in JIRA
https://jira.esss.lu.se/browse/SASVIEW-1132

On Mac, only the following error message is displayed in the Log explorer:
"ERROR: Unknown property axisbg"

matplotlib > 3.0 doesn't have axisbg property for Axes. it is now 'facecolor'. The orientation viewer runs from sasmodels.
We will downgrade matplotlib on linux/mac until proper rewrite of sasmodels is done. mpl 3.0 is not yet available for windows on conda, so we didn't see the issue before.

So I think this means we need to check if sasmodels is now MPL 3 compliant and if so, just enable the viewer.

[rozyczko]

This needs some work now. When no plots are shown, the orientation viewer performs as expected. When a plot is shown, it gets replotted in a separate window, and the original plot canvas turns blank.