Extends Big Bang using Values

Package Merge Request

Changes

Adds Helm templating to extend BB using values for mission apps. This is a proof of concept and should not change the behavior of the current chart. Additional issues will be opened to scope out the remaining work for releasing this in BB 2.0.

Areas that require extra review: _helpers.tpl changes; Making sure all new files will NOT generate anything using existing Big Bang 1.x values.

A values2.0.yaml was added that can be used for dev testing.

For Issue

Closes #1359 (closed)