fix: adjust payload keep alive values to be in ms

[petragabriela]

Changing the keep alive interval and keep alive max lifetime values to be in milliseconds according to the documented protocol.

Motivation:

Currently, the master branch is not really usable because the setup payload sent to a server includes a max lifetime value in seconds while it should be in milliseconds according to the protocol. As a result, the channel will be prematurely closed before the client can receive the response.

Modifications:

• Added Ms to instances variables related to the keep-alive for better clarity
• Changed their default values to be in milliseconds
• Changed the keep-alive timer param to be in milliseconds
• Minor fix in WebSocketRSocketResponder: add casting

Result:

No breaking change is expected, the keepAlive setter of the RSocketConnector class still receives the params in seconds unit.
Now RSocket channels should not be prematurely closed.

References:

Protocol Doc
Kotlin SDK
Go SDK