Adjust login sequence and provide more descriptive errors

Move the login to Coverity server and retrieve project information for the stream so that then only defect querying is needed to obtain data for the report. Because of this single time login the error checking has simplified as we can now fail (or not) even before build starts, but that also means we just produce a warning (not an error and sphinx build crash) when something is wrong with configuration, network or coverity server and render an empty table. It is now upon user to catch that sphinx warning and react upon it if required.

Recommendation for this is that Sphinx is run with mlx.warnings plugin (or that error log is piped through it).

Fail more gracefully

A bit more intense and user friendly exception/error handling which is more inline with the sphinx terminal output. Also in case you do not add username/password (but would still like to build) it now proceeded without error (just a notification that it failed during the build and generic text instead of table).

Restore latex compatibility

The 0.0.7 release had a bug which prevented document to be rendered because table row with error/success message did not have enough columns.

Better user experience with empty stream

Mostly people start with empty streams in Coverity (and maybe even without it). Make it a bit more user-friendly and do not error out on such occasion.

More informative messages when errors

Add some more informative messages when there are unexpected errors in the data obtaining. Always try to not break the build in case something not important has failed.

Better handling when no connection

This version mainly fixes the problems that plugin caused on systems without connection to Coverity server. Now we fail more gracefully and don't stop the process.

Added also a simple link parser for the comments.

Fixing the basestring fail in python3

Adding flake to detect on python3 errors as well.

Python3 support

Provide python3 support

Alpha release

Due to fixing of the ci new tag.

Initial alpha release

First version of plugin working on local Coverity installation.