Temporary labs are the new default. Static labs have not been used for
some time in the reporting framework. They are obsolete.
Adjusts or removes many, and hopefully all, references to static labs.
Removes function arguments, subroutines and instance methods related.
Removes environment variables and constants. Adjust the documentation
Also removes 'frontend/lintian-lab-tool'. Does not remove lab queries.
Temporary labs can still be kept after a Lintian run by specifying the
command line option '--keep-lab'.