Implement library/standalone tool shed install functionality.

[jmchilton]

• Introduce a MyPy Protocol that describes what part of "app" is consumed by essentially all the tool shed install and management code - called InstallationTarget.
• Implement a standalone class (StandaloneInstallationTarget ) that doesn't depend on anything in galaxy-app and can be used to install tools, repositories, data managers, etc... into a directory, manage a simplified toolbox, manage tool data, etc...
• Introduce an abstraction for the client interaction in the tool shed tests and move all existing implementation details into a "Galaxy API" version.
• Introduce a second test client interaction implementation that uses a StandaloneInstallationTarget - update CI to run tool shed tests against both in a matrix strategy - so we are testing the Galaxy API as well as the new client install library functionality.

Builds on:

• Move ToolShedRepositoryCache into galaxy.tool_shed. #14824
• Move base tool data infrastructure into tool_util package. #14822
• Remove legacy reinstall endpoint from admin_toolshed.py. #14811
• Dozens of already merged PRs obviously.

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[mvdbeek]

Suggested change

from uvloop import install

[jmchilton]

I want the testing from #14906 before merging this line of work. I'm going to close and reopen a new slice at this once I've figured out testing better.