configure: bump required bitlbee version to 3.2.2

As of bitlbee-3.2.2, the pkg-config file now contains properly defined
variables. The plugin is now able to use pkg-config as a reliable means
of version checking. In addition, the version bump allows the plugin to
remove some compatibility code in the steam-json interface.

This fixes a compile time warning in the steam-json interface.
steam-util: added SteamUtilEnum array nullifier macro
steam-util: implemented debugging utilities
steam-id: implemented the SteamID interface

This implements an elegant interface for working with 64-bit SteamIDs.
The interface is implemented with only a simple series of macros, which
eliminate the need of storing the SteamID in abstract data formats. As
are result, the steam-id interface requires very little memory.

This removes the existing SteamID implementation within the steam-user
interface.
steam-crypt: implemented cryptographic interface

Currently, the plugin handles some cryptographic operations internally
via GMP. However, as time has progressed, it is has become evident that
this is not practical. This was done initially to prevent from having to
implement and maintain the three different SSL libraries which bitlbee
supports.

Advantages of libgcrypt:
  - Available on most systems
  - Has the required cryptographic implementations
  - Prevents the implementation of three SSL libraries
  - Required by bitlbee for OTR support

The cryptographic interface is based on libgcrypt. As a result of
introducing libgcrypt, GMP is no longer needed.