Revert "Disabled changes regarding target variant, added mail notification for build completion"

This reverts commit 6c0044504c3f30bee381de616a5967f1ce3846da.
Revert "Buildscript > If -o3 do a user build instead of userdebug"

This reverts commit 97e684395934213ba272e16d7ffac63aed790a31.
Readded mail noti