purl-next: Implement updated PURL test suite in packageurl-rs

[pombredanne]

Implement updated PURL test suite in supported programming language libraries - one batch - packageurl-rs

[pombredanne]

This is completed with this PR:

• Run tests using reference data from purl-spec packageurl.rs#1

This is also submitted upstream:

• Run tests using reference data from purl-spec scm-rs/packageurl.rs#27

This uses the PURL specification tests suite.