Nicer, less-fucky buildinfo

[aakatz3]

Is your feature request related to a problem? Please describe.
It's troubling, annoying, and potentially problematic that the way build info is currently placed into stickyapi is by doing a string replace on all files, and moving them to a processed build location.

Describe the solution you'd like
I propose a generated-sources source set, where a buildinfo class is created and placed, by extending features from the current versioning plugin

Additional context
I already have a beta of this in StickyGradleTasks