Split RFCOMM channel signals into Remote and Local pairs. Use memcpy() to copy over data from the command parameters to the RFCOMM response parameters.

Ensure that only the valid parameter bytes are sent back in response to MSC commands.

Add TEST RFCOMM command handler. Remove the RFCOMM channel UseUIFrame element, as the Bluetooth adaptions to RFCOMM only allow UIH frames to be used.

Rename RFCOMM_GetFrameDataLength() to RFCOMM_GetVariableFieldValue() as it is multi-purpose, and modify it to move the buffer pointer itself rather than relying on the caller.

Make RFCOMM_GetChannelData() return NULL if the required channel DLCI is found, but the channel is closed.

Add modem signals (BREAK, DCD, etc.) to the channel state array, and add in a handler for the Modem Status RFCOMM control command.

Add missing BT_* prefix to the Bluetooth stack's channel state enum values.

Split out the RFCOMM Control Channel command processing code into a seperate set of files for clarity.