sbf: Fix configuration messaging

[niklaut]

If the GPS is already transmitting data messages (starting with $@), their payload contains \0, which makes strstr difficult to use since the search buffer "terminates" before a $R reponse is found.

• [x] Fix finding ACK when binary messages are received before.
• [x] Fix finding COM/USB port when binary messages are received before.
• [x] Fix finding COM/USB port when anything is received before (used wrong offset).
• [x] Fix reset commands (they where not detecting ACKs).
• [x] Fix detecting negative reponses $R? instead of $R:.
• [x] Fix not ignoring baudrate argument.
• [x] Fix configuration while GPS is already running.
• [x] Fix sending messages too quickly.
• [x] Integrate message formatting into sending functions to remove clutter.
• [x] Remove duplicate message sending due to non-functioning ACK finding.
• [x] Remove disabling of outputs, it's not necessary if ACK finding works
• [x] Add more (short) warnings to figure out what part of the config failed in the field.

Examples of hardware testing:

Cold boot vs hot boot.

Command - Binary message - Response

Hours of hot and cold configurations.