Add security/p5-Crypt-XTEA, and its dependency lang/p5-Scalar-Util-Numeric.

Crypt::XTEA implements the fast and light XTEA cipher that supports the
Crypt::CBC interface.

https://metacpan.org/pod/Crypt::XTEA

Scalar::Util::Numeric implements some scalar classification routines
with an XS module.

https://metacpan.org/pod/Scalar::Util::Numeric