Token support for 3rd party key managers without subscriptions

[RakhithaRR]

Problem

Some users might have the requirement to consume the APIs directly using the tokens obtained from their Identity Providers without going through the subscription process in APIM

Solution

Introduce a new API level configuration to disable the subscription validation when consuming the API. This should be a version specific configuration. i.e. the configuration should be read-only when set once and should only be possible to change this when a new version of the API is created in order to avoid issues with the API consumers.

Affected Component

APIM

[RakhithaRR]

The following scenarios should be handled when implementing this feature

• [x] API level configuration to enable or disable subscription validation.
• [x] Publisher UI changes to support the new configuration and scenarios where subscription validation is disabled.
• [x] Devportal UI changes to support APIs which have subscription validation disabled.
• [x] Application/Subscription level rate limiting changes
• [x] Analytics for APIs without subscriptions
• [x] End user token generation for APIs without subscriptions
• [x] Backend validations for different scenarios
• [x] UI and Integration tests
• [x] Documentation