Generalize install code to be reusable by all install methods

[oubiwann]

OLP installs can make users' lives a bit easier:

• update PATH to point to LFE/OLP binaries
• update PATH to point to erl, erlc, etc., in the erts release dir
• start lfe and erl with the -boot parameter, pointing to the correct boot file

Right now, the only place we're installing OTP is in the experimental/testing Docker image (to /opt/olp on the guest OS). As such, we've got some custom setup in the Dockerfile -- this needs to be broken out, generalized for use by all install methods, and with the appropriate bits made optional, etc.

Tasks:

• Create bash profile inclusion for OLP installation - Create bash profile inclusion for OLP installation #42
• Update the Docker build to use this
• Create additional files as neccessary
• Update other install methods to use the same files

Part of epic #37