[decode-syseeprom] When reading from DB, display CRC-32 and all Vendo…

…r Extensions (sonic-net#1497)

Changes when reading system EEPROM values from State DB (`decode-syseeprom -d`):
- Display CRC-32
- Display all present vendor extensions
- Display hex TLV code with lower-case `x` to match the output when reading directly from EEPROM
- If a TLV code is not available, omit it from the output rather than displaying 'N/A' for all fields