Clean-up Activator class, may be filly removed after TemplateExtension
rework.
Logging code should be less verbose after merging of
https://git.eclipse.org/r/#/c/160386/
Change-Id: I502e14ac40b3ae5d3850b195f9ad9177bfae5536
Signed-off-by: Alexander Fedorov <alexander.fedorov@arsysop.ru>