goarch: Move Go architecture mapping to a library

goarch: Move Go architecture mapping to a library

Other spaces uses the Go architecture definitions as their own (for
example, container arches are defined to be Go arches). To make it
easier for other places to use this mapping, move the code that does the
translation of OpenEmbedded arches to Go arches to a library.

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>