Add RTCM Subscriber node to enable RTK GNSS Zephyr drivers

[ubieda]

To enable Native Zephyr GNSS drivers in CogniPilot.

Expected outcome:

• Cerebri (on VMU-RT1176 with RDD2) works with UBX F9P module with RTK. (assuming a ZROS node publishes RTCM3 data)

[ubieda]

Firmware-side Addressed by:

• rdd2: Add RTK support cerebri#273
• repo: Add RTCM3 sub through ethernet spinali#12

Requires:

• Definition of MR-MCXN-T1 BSP for GNSS shield.
• Definition of Synapse ROS RTCM3 message.
• Sending RTCM3 frames from ROS2 workspace.