Add Bufr Converter for SSMIS

[XuLu-NOAA]

This is to document the process of adding Buffer converter for SSMIS
Step 1 - create mapping and Python script

1. Modify the bufr_atms_mapping.yaml and bufr_atms.py to adapt for ssmis.
   One possible concern, the Sensor Zenith/Azimuth Angles are require by JEDI, but not in the bufr file. It contains a query: "*/SCLINGEO/BEARAZ", which corresponds to the sensorAzimuthAngle according to the bufr table. But this variable is empty and gives additional dim2 of 28. This looks suspicious, I'll create a 1-d array with -1 values for initialization. The SnsorZenithAngle is fixed to 53.0 according to the SSMIS.

Step 2 - add ssmis spatial averaging into bufr-query
1. Changes are made to
bufr-query/core/src/bufr/BufrReader/Exports/Variables/RemappedBrightnessTemperatureVariable.cpp
bufr-query/core/src/bufr/BufrReader/Exports/Variables/Transforms/ssmis
bufr-query/core/CMakeLists.txt
2. options are added to remappedBrightnessTemperature section in bufr_ssmis_mapping.yaml:
sensor: ssmis
method: 1
satelliteId: "/SAID"
latitude: "/CLAT"
longitude: "*/CLON"
If not given, it will read in as atms sensor by default and ignore the method/satelliteId/lat/lon fields.

Examples of the filtered observation space differences:

Examples of the omb differences in the regional domain: