Internal purchase controller refactor

[super-bryan]

Changes in this pull request

• Allows an internal purchase controller (termed "automatic purchase controller") to be used identically to an external purchase controller
• Order of initialization in the DependencyContainer no longer matters
• Fixes issue with tests that could cause some dependencies to not use the mocked dependencies (can explain more if you want after seeing the PR)
• Removes redundancy of providing dependencies with a set of parameters and a factory that provides those same parameters
• Uncouples ReceiptManager logic from the original purchase controller
• Moves receipt logic from the StoreKitManager into the ReceiptManager
• Removes the need for if/else logic when it comes to purchase controller logic
• Removes all use of unowned variables
• Removes force unwrapping in the dependency container
• Uses the adapter pattern only when necessary (i.e. only for objc types)
• Makes classes more protocol-oriented to avoid tightly coupled classes

Checklist

• All unit tests pass.
• All UI tests pass.
• Demo project builds and runs.
• I added/updated tests or detailed why my change isn't tested.
• I added an entry to the CHANGELOG.md for any breaking changes, enhancements, or bug fixes.
• I have run swiftlint in the main directory and fixed any issues.
• I have updated the SDK documentation as well as the online docs.
• I have reviewed the contributing guide