library: move Osmocom_Types.Arfcn to GSM_Types.GsmBandArfcn

In some cases GsmArfcn itself is not enough.  It case of L1CTL
and GSMTAP, it needs to be equipped with a band discriminator:

  - DCS / PCS (as the numbers may overlap),
  - Downlink / Uplink (not yet there).

Let's rename this record and move it to GSM_Types.  Also, add
send / receive tamplates, so we can add new fields later.

Change-Id: I7a63f03bbd15a06caafb786122dc12991d115771
8 files changed