Documentation and tests for new APIs

[henrypinkard]

Help/PRs appreciated with these!

Tests

• Change github action tests to automatically run on python backend and with RAM saving as appropriate
• Tests for notification callback function
• More tests for adaptive acquisition/acquisition future API
• RAM datasets with java backend and Dataset API (is this possible/advisable)

Docs

• Add instructions for how to install programatically
• Add figure showing python backend for headless mode https://pycro-manager.readthedocs.io/en/latest/advanced_usage.html
• Add description of features available in java vs python backends and the potential relative performance of each (and maybe scripts that assess relative performance)
• RAM Datasets and potential pitfalls.
• Notification callbacks
• Adaptive/asynchronous acquisition API
• #673

[henrypinkard]

#794