allow instrument package installation by pip

[prjemian]

Make it easier to use the same instrument package in both IPython console sessions and Jupyter notebooks (includes Jupyterlab). Refactor into an instrument package that can be installed locally via pip.

pip install -e .

This will install the package and allow local modifications of the source files to be used right away. (Modification of content in this package usually means a restart of the ipython session or restart of the jupyter kernel will be necessary to begin using the modification.)

Then, whether in console or notebook, from instrument.collection import * will load the instrument configuration without need to start in a special directory or modify the sys.path.

NOTE: This will change the structure of the repository from an ipython profile to an installable Python package.

relates to #148 and #151, see example: https://github.com/prjemian/ipython-poof/blob/master/README.md

[prjemian]

This issue should also consider and describe what will happen with the user and spec_support directories.

[prjemian]

Needs some thought because of these two directories. Won't happen in time for operations to start this week. Moving to later milestone.

[prjemian]

This is working for the instrument as-is now. A change would introduce confusion, at least at first and is not absolutely necessary. Will not implement this change.