Remove validator

[mbasaglia]

It's going to be moved to the main site

[Aidosmf]

should we remove:

1. tools/validate.js?
2. schema-validate.py?
3. .github/workflows/test-animation?
4. validate mentioned at "docs/editing/schema.md"?

[mbasaglia]

None of them refer to the smart Lottie validator:

1. tools/validate.js?

This is the script that validates the test files from the raw schema, doesn't use the validator

2. schema-validate.py?

This checks the schema itself

3. .github/workflows/test-animation?

This uses validate.js above, not the new validator

4. validate mentioned at "docs/editing/schema.md"?

This mentions the schema-validate script

[b-wils]

Changes look good, going to wait until this is on the main site to approve.