[Masternode] Manage status cleanup

[furszy]

Focused on two changes inside the active masternode state manager function:

1. Removed a redundant MN address parsing and port validation (both are covered at startup inside initMasternode).
2. Modified the inbound connection availability test to not add the self-connection to the connection manager peers vector (as it makes no sense to have it, nor maintain it). This change fixes the scenario in which the node connection already exists locally and the node invalidly logs the "Could not connect to xxx". Plus, changed the logging in the area to be more understandable as well.

[random-zebra]

utACK 264aba8

[Fuzzbawls]

utACK 264aba8