New cleaned R27 table (SENSOR_MODEL): documentation & NVS implementation steps

[cgourcuf]

• Publish Argo User’s Manual with updated definition of the meta variable SENSOR_MODEL & Char SENSOR_FIRMWARE_VERSION(N_SENSOR,STRING32)

• Update R27 according to the new constrained vocabulary that will allow identification of similar sensor models easily for monitoring - see https://docs.google.com/spreadsheets/d/1GcpM4PoCnsZf_2jw6EpinoxB4eittFufAJrxNyEutKQ/edit?usp=sharing

• Current R27 entries that are no longer needed will be deprecated

• Two additional R27 entries will be added

• Managers of R27 will use new definition to accept new entries

• When ready, SBE can include both SENSOR_MODEL and SENSOR_FIRMWARE_VERSION in the JSON schema to deliver sensor/float metadata