bundle: Add support for activating multiple bundles

This moves the implementation of the bundle activation API's into
the `bundle` package and makes them public. We are also beefing them
up so that they can handle >1 bundle at a time, compile additional
modules, and more. They kind of becomes a one-stop shop for getting
data and rego ready to evaluate.

Signed-off-by: Patrick East <east.patrick@gmail.com>

squash! bundle: Add support for activating multiple bundles

Signed-off-by: Patrick East <east.patrick@gmail.com>