Added install make/tox recipes; modified contributing doc

[derek-globus]

What?

• Added a new tox environment: install-venv which installs a tox environment as though it were a virtual environment at ./.venv
• Added a new make recipe: make install which installs a virtualenv and pre-commit
• Update the contributing docs

Why?

The steps to get an IDE set up to function with the SDK is not apparent from the contributing docs.

Even if IDEs are not the exclusive development environment used by sdk contributors they are a core one. We should have a simpler path to encourage contribution from new contributors.

Testing

make clean && make install