The OID module is used by both crypto and X.509. It has moved to the
`tf-psa-crypto` subdirectory, and the sibling commit
08d8cc57db removes this subdirectory from the
`mbedtls` repository in order to make `tf-psa-crypto` a submodule. We want
to access the relevant parts directly from X.509 rather than go through the
crypto repository, because OID functions are only accessible as private
interfaces, and crypto doesn't know when a particular OID function is needed
in the build since it depends on X.509 configuration options.
Make a copy of the OID module and its unit tests. In a follow-up, the X.509
module will switch to consuming this copy rather than the one that went into
TF-PSA-Crypto.
Rename the files from `*oid*` to `*x509_oid*` to follow the naming
convention that submodules of X.509 are prefixed with `x509`. This also
avoids file name clashes with TF-PSA-Crypto.
Since OID is not a public interface of Mbed TLS 4.x, move the header file
into `library`.
This commit only makes the files available. Subsequent commits will take
care of making these files used in the build.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
