Load interpreter from maven repository

Zeppelin loads interpreter binaries (jar) from /interpreter/[INTERPRETER_NAME] directory and configured by zeppelin.interpreters property or ZEPPELIN_INTERPRETERS env variable.
They're loaded when Zeppelin is starting up.

We can make REST API that loads interpreter binaries from maven repository and configure it on runtime.

It gives two major advantages.

• We can reduce size of Zeppelin binary package distribution by releasing interpreter as maven artifact and let user load them online, on runtime. Instead of packaging all dependencies in a distribution.
• Using 3rd party interpreter is much easier.

REST api would look like

Load

/interpreter/load/[interpreter group name]/[interpreter name]
params:
   artifact - maven artifact (groupId:artifactId:version)
   className - Interpreter class
   repository (optional) - additional maven repository address

Unload

/interpreter/unload/[interpreter group name]/[interpreter name]