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.

Change-Id: I84f7d4f4a803e6e52bf2021c6c74917e90bbc846
Fixes: 29978908