Replace local.* properties and profiles by Maven mirroring

Currently, we deal with optimization for Jenkins by multiple local.* properties and local.* profiles.
Those properties and profiles are just used in order to replace repository URL.
Maven has the concept of mirroring for that, and without adding a profile, we can tell Maven to consume another URL for a given repo. Moreover, Tycho will support mirrors for repo in .target files starting from 0.16.0.

WE should move to the mirror approach since it keeps things clear and separate issues: pom describe build, mirror allow to override repo without any change.

Seems like Maven supports having 2 settings.xml files as input (one with -gs and one with -s), so no big difficulty here.