[DEV-165] New exported function for modules.
[DEV-165] Factor out send function
[DEV-165] retry servers in the same priority group
Add retry PV
Improve server param parsing
[DEV-165] Add high water mark (hwm)
[DEV-165] Schedule to close/reconnect servers based on pending requests

- with exponential back-off
[DEV-165] Add retry for timeouts and failures to send.
Move jsonrpc_request to jsonrpc_funcs
Separate request related functions into a new file.
Decrement for any message on a socket
[DEV-179] Refactor reconnection logic
[DEV-179] Handle failures to send
Fixup tried_servers logic
Initialize the jsonrpc_request_retry global
Unnest sending logic
little fixes
retry forever (-1), retry never (0)
refactor request creation
fixup request