New pairing database

Goal is to write individual pairings (bonds) to separate file and have a more flexible file format. Currently all pairings (bonds) are stored in a single file (pairings.bin).

Goal is to store each pairing (bond) in a separate file in a pairings/ directory, named pairingN.bin (with N being 1,2,3,...). Each file stores a list of TLVs and has the version of the file format as first byte.

What I still want to implement:

• Remove ble.txt and mac.txt and use card10.cfg instead.

In the future I'd like to be able to read the other device's name after pairing and write that into the file so the user has an idea which device is represented by that pairing.