feat: add path parsing to BasicShape

[noahbald]

This PR adds support for parsing and minifying path definitions, such as clip-path: path('M0 0L10 10') which would be minified as clip-path: path('M0 0 10 10')

See here for tests, which covers all the path optimization related tests from SVGO

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To finish for this PR

• [x] Implement serde derives
• [x] Implement Visit derive
• [x] Implement json-schema

[noahbald]

Hi, starting this as a draft as this a first-time contribution. Let me know if I've missed anything!

[noahbald]

Closing this so that I'm not using master in my fork, will re-raise soon