Implemented all metadata queries/reports

Queries (1-minut-pulling mechanism):
 * RSSI
 * Mode and submode
 * Camping operator
 * LAC and Cell ID

Reports:
 * ^RSSI
 * ^MODE  Mode and submode
 * +CGREG LAC and Cell ID
 * ^CSNR: rscp and ecio
 * RRC state