Export `ProxyOptions` from CosmosClientBuilder API instead of `InetSocketAddress`

[kushagraThapar]

• Export ProxyOptions from CosmosClientBuilder API instead of InetSocketAddress
• Currently cosmos only supports HTTP proxy through reactor netty client.
• ProxyOptions from azure-core enables end user to setup proxy for HTTP, SOCK4, and SOCK5
• Short term plan is to support HTTP proxy but open the API to all types of proxy using ProxyOptions
• Long term plan is to update the implementation of reactor netty client to support all 2 types of proxies.

[anuchandy]

There is also an implementation of Digest Proxy auth in azure-core-netty module. Given cosmos has its own reacttor-core HttpClient, probably this package is something that could be vendor-ed in cosmos impl package if there is an ask for it in cosmos.

[kushagraThapar]

This is done.