Add auto validation for Actors Examples

[mukundansundar]

Describe the proposal

Add auto validation for Actors Java Examples. Follow the guides/examples in https://github.com/dapr/mechanical-markdown for more information on the validator used.
Similar to the PR #464.
Add the test for the actors example. It might need some changes to make the output deterministic enough for it to be validated.

[mukundansundar]

Need out of order processing support from mm.py. Since there are 3 actors in the example that are there which are called from independent threads, there is no order guarantee on which actor is called first. Similarly for the reminders and timers, since there is more than one actor, any actors can be pinged first or reminded of a state first.

Created an issue dapr/mechanical-markdown#18 to add ability to mm.py for outoforder processing.

The other option here is to limit the example to a single actor and then use the current available validations in mm.py.

@artursouza thoughts? Personally I do not like changing the example and limiting it to a single actor call.

[artursouza]

@mukundansundar I agree. We need out of order processing before we can add this validation.

[tanvigour]

/assign