Make Transforms Unidirectional

Convert the IpSecTransform from being a bi-directional
pair of SAs to a unidirectional single SA. This CL
also removes the concept of "direction from SAs meaning
that a IpSecTransform may now be applied to a socket
in either direction.

-Make transforms unidirectional
-Add Convert allocateSpi() to use destination rather
 than direction and remote address
-Remove directionality from builders for IpSecTransform
-Change applyTransportModeTransform() to take a
 direction in which to apply the transform object.
-Additional minor naming updates
-Restrict IpSecConfig to only print keys on eng builds
-Move DIRECTION constants to IpSecManager
-Add sourceAddress parameter to IpSecTransform to provide
 additional guarantees about the source address of data;
 (explicit failure rather than implicit failure).
-Move SPI to the build() method of IpSecTransform

Bug: 71717213
Test: runtest frameworks-net, CTS - IpSecManagerTest
Change-Id: I0824b37f443f4b8c62536d9801238c63ed8f2a1c