tlsprofiles: add SecP256r1MLKEM768, SecP384r1MLKEM1024, and secp256r1 alias (#2754)

Add the two NIST-curve ML-KEM post-quantum hybrids introduced in Go 1.26
to the custom curve map and local constants. Also add "secp256r1" as an
alias for "prime256v1" using the IANA name for P-256.

Signed-off-by: Todd Short <tshort@redhat.com>
Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>