Eleven: the great cleanup

- Remove all java dead code
- Update deprecated methods / classes calls
- Kill all the {@inheritDoc}s
- Minor code style fixes (fields -> local variables, final, indentation...)
- Make use of newer java lang features (lambdas, try catch resources...)
- Update copyrights to be consistent

Signed-off-by: Joey <joey@lineageos.org>
Change-Id: Ic9e3bbd3e82fa4ea2e87e683a99340fba4974beb