Resolve "Create protobuf file for interacting with a maven image"

Overview

This MR covers the creation of a protocol buffer file for interacting with a maven server.

The message we will send to a maven server contains the following:

• phase: the phase(s) in the maven lifecycle we would like to call
• pluginGoal: any plugin goals we would like to use
• args: any maven command line arguments we would like to pass to the maven server

For example, if we want to call mvn clean install -DskipTests, the breakdown would be the following:

    |---phase---| |---args--|
mvn clean install -DskipTests

or if we want to run a specific plugin along with arguments, it would be treated as the following

    |--pluginGoal-| |-------------------------------------------args------------------------------------------------------|
mvn dependency:get  -DgroupId=org.apache.maven -DartifactId=maven-core -Dversion=2.2.1 -Dpackaging=jar -Dclassifier=sources 

Tasks

• Update docs if needed (workflow, runbooks, README, migration metrics, etc.)

Acceptance Criteria

• Existing UTs pass locally

@gitlab-org/professional-services-automation/tools/migration

Closes #781 (closed) #785 (closed)