Update pull request base branch

Update pull request base branch from `master` to `develop` in the contribution instructions.
Adding latest unstable release and license badges
Initial documentation version for ReadTheDocs
Finalizing documenting `@find-by` annotation
Writing documentation

- added "Getting Started / Configuration"
- described "@page-url" annotation
Describing `@timeout` annotation
Describing `@element-name` annotation
Some concept terms added
Removing website page concept
Changing order of concepts
Updated docs build manual to indicate Shynx-AutoBuild usage
Adding placeholders for new documentation pages
Adding documentation build status badge