AWS streams: Introduce `dynamodb` and `kinesis` events, deprecate `stream`

Initially discussed here: https://github.com/serverless/serverless/issues/8117#issuecomment-680727895

Use case description

To avoid ambiguity it'll be nice to handle both stream types with two distinct event types.

Benefits of that change:

• Event source type is clear upfront at event defitnition
• Internally we do not have to resolve event source type from ARN (and possiblities of that are limited)
• Allows to improve property naming (e.g. batchWindow and maximumRecordAgeInSeconds doesn't seem to follow same convention)
• Allows to address inconsistencies and bugs as:
  • In stream event default batchSize to 10 while on AWS grounds default is 100
  • In stream 0 is not recognized value for batchWindow, while it is a supported value o AWS grounds (fixed with https://github.com/serverless/serverless/pull/8202)

Proposed solution

1. Deprecate currently implementedstream event
2. Introduce kinesis and dynamodb events, but configure them with same AWS::Lambda::EventSourceMapping resource generator.
   As we need to leave stream event working as is, I believe this should be introduced as new implementation.
   List of properties to be supported by those events (note new naming in some cases):

• batchSize: optional, maps to BatchSize
• bisectBatchOnFunctionError: optional, maps to BisectBatchOnFunctionError
• onFailureDestination: optional, maps to DestinationConfig.OnFailure
• arn: required, maps to EventSourceArn
• maximumBatchingWindow: optional, maps to MaximumBatchingWindowInSeconds
• maximumRecordAge: optional, maps to MaximumRecordAgeInSeconds
• maximumRetryAttempts: optional, maps to MaximumRetryAttempts
• parallelizationFactor: optional, maps to ParallelizationFactor
• startingPosition: optional (but required in AWS), maps to StartingPosition and we should map to TRIM_HORIZON as default (as in case of stream event)

3. New events should be backed by new tests, configured with runServerless util (follow: https://github.com/serverless/serverless/tree/master/tests#unit-tests). Integration tests should be also introduced (we may reuse those already configured for those events, but it'll also be good to keep testng stream event)
4. Documentation should be updated to document dynamodb and kinesis as separate events (it's fine to remove documentation for stream event)

Locate the existing stream event implementation and its shared AWS::Lambda::EventSourceMapping resource generator. Read the unit-test guidance around runServerless, then inspect the existing integration tests for stream events. Done means separate dynamodb and kinesis events, compatibility handling for stream, updated unit and integration coverage, and documentation for the new event names.