Bug 546611 Switch to bnd to generate OSGi metadata

* Switch to BND for OSGi metadata generation,
* update AspectJPlugin,
* remove task wrapper (Pinned to Gradle version 3.5) and
* switch from FindBugs to SpotBugs

Also migrates the build scripts to Gradle 5.6.2.
Note: The upgrade was a prerequisite for using a resent BND
Gradle plugin.
Note: Virgo Nano related smoke tests have been @Ignored.

Change-Id: Ifba8a03d64b512487c6cba4ad4730029a5ea78d2
173 files changed