www/gatling: Update version 0.15=>0.16
- Update MASTER_SITES to https scheme
- UNBREAK
- Remove DEPRECATION
- Utilize USES=localbase:lkdflags and refactor
- Refactor ambiguous VARS like bin asnd sbin
- Refactor make makepatch compatible patches
- While I(bofh) am here pet portclippy/portfmt/OPTIONSNG
PR: 253763