Remove position dependent lookup tables in AT command parser

The various position dependent lookup tables in the AT command parser
were out of sync, causing invalid responses to the AT+CBPS command for
example.

This patch gets rid of positionally dependent enums for simple lookup
tables that correlate all the values for easier, less error prone
maintenance of the related tables.

This re-instates a previously reverted patch after fixing incorrect
field order in tBTA_AG_INDICATOR_MAP.

Change-Id: I7f8a052e78706c8c72c5102b38cfe9ce200ae0d9
Fixes: 29978908