OAuth refactor: create hooks implementation

[thekaveman]

Currently

• Usage of the benefits.oauth.analytics module functions are sprinkled throughout the benefits.oauth.views , benefits.oauth.redirects , and benefits.oauth.middleware modules.
• Usage of sentry_sdk.capture_exception() is also sprinkled throughout the same files

Refactor

• DefaultHooks provides definitions to plug into specific points in the integration with IdG
• cdt_identity implements the views and redirects necessary for this integration, we won't need these in benefits anymore
• benefits can provide a custom hooks implementation

Acceptance criteria

• Define a custom hooks class e.g. benefits.oauth.hooks.OAuthHooks inheriting from cdt_identity.hooks.DefaultHooks
• All calls to benefits.oauth.analytics functions happen within the corresponding custom hooks classmethod(s)
• All calls to sentry_sdk.capture_exception() happen within the corresponding custom hooks classmethod(s)
• All overridden classmethods call their corresponding DefaultHooks classmethod to start