Pass through unknown tags and attributes

[unexpectedpanda]

At the moment Retool only takes select tags and attributes from a DAT file's titles, and rebuilds them to a sanitized version. These include:

• <game>, with the name attribute.
• <category>
• <description>
• <rom>, with the name, size, crc32, md5, sha1, and sha256 attributes.

Ideally for future proofing, when encountering unknown tags or attributes Retool should copy them as-is into the output DAT file.