Revert "bridges/bridge_t38: Add a bridging module for managing T.38 state"

Revert "bridges/bridge_t38: Add a bridging module for managing T.38 state"

This reverts commit 6614babea27fbafbe11820ea03737dd5c4f9ecec.

Unfortunately, using a bridge to manage T.38 state will cause severe deadlocks
in core_unreal/chan_local. Local channels attempt to reach across both their
peer and the peer's bridge to inspect T.38 state. Given the propensity of
Local channel chains, managing the locking situation in such a scenario is
practically infeasible.

Change-Id: Ic687397ffea08dfb899345a443bd990ec3d0416a