Move Maven support to //tools/maven

Rewrite the Maven tool to accept a spec of things to process on the
command line and use $(location) in the invoking genrule() to locate
the necessary files from Buck.  This gets rid of special cases in the
mvn wrapper tool and allows the definition to be given completely from
Buck as part of the build description.

Maven needs to be single threaded to perform repository updates safely
so only one genrule() target is declared to buck for the deploy or
install action. The rule is given all artifact information in a single
pass, allowing the mvn.py wrapper to execute them.

Change-Id: Idbcf645b69280420987a0e8f52947ba93ac9e6f0
9 files changed