EmbeddedPkg BeagleBoardPkg: move special HOB reuse libraries into platform

EmbeddedPkg BeagleBoardPkg: move special HOB reuse libraries into platform

The BeagleBoard platform uses PeCoffLib and CustomDecompressLib
implementations that invoke the library code that resides in the PrePi
module via pointers exposed via special GUIDed HOBs. This is a nice hack,
but not necessarily something we want to carry in reference code.

So as a first step, move the libraries that expose this reused code into
BeagleBoardPkg, and remove it from EmbeddedPkg.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>