Part of umbrella issue #16
Bleeds into #114 a little bit.

These changes are going to take a while, but they are close to done. Adding API factories should require some slightly complicated upfront work, but should make it easier to add new features over time, while making our plugin align more with modern Backstage community practices.

Requirements

Should have

• Codebase should be refactored to use API factories
• We should have some kind of solution for making data from the API factories available within React UI in a safe way (the React data should be immutable UI state, even if the API factories themselves have mutable class state)
• Tests should be updated to account for new dependency injection mechanisms that the factories provide