Revisions to Status system

[rcahoon]

Description

• Use static methods where possible to minimize boilerplate code: we don't need to keep writing getInstance(), and we can use import static so we don't have to keep writing StatusBus. or Conditions.
• Remove Status parameter from Request#isDone. The isDone method can just access the StatusBus directly/statically.

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Be detailed so that your code reviewer can understand exactly how much and what kinds of testing were done, and which might still be worthwhile to do.

• Unit tests: Units tests for new functionality are included in this PR
• Simulator testing: [Add your description here]
• On-robot bench testing: [Add your description here]
• On-robot field testing: [Add your description here]

[rcahoon]

Use mixin interface instead of static methods