Upgrade docusaurus to version 3

[maxwolfs]

See the Migration Guide: https://docusaurus.io/docs/migration/v3

It will have some breaking changes.

Upgrade complete but the build is still failing due to some remaining errors that must be fixed in other repositories. See the summary:

MDX Compilation Errors

• standards
• k8s-cluster-api-provider
• release-notes

Components

k8s-cluster-api-provider:

doc/Upgrade-Guide.md (line 111, column 20): Unexpected /, expected a name-starting character.
doc/requirements.md (line 15, column 24): Unexpected /, expected a name-starting character.

Releases

ReleaseX.md (line 4, column 39): Unexpected Y after self-closing slash, expected >.
Release1.md (line 35, column 8): Unexpected /, expected a name-starting character.
Release4.md (line 78, column 160): Unexpected /, expected a name-starting character.

Standards

scs-0100-v1-flavor-naming.md (line 92, column 76): Unexpected 2, expected a name-starting character.
scs-0100-v2-flavor-naming.md (line 121, column 76): Unexpected 2, expected a name-starting character.
scs-0100-v3-flavor-naming.md (line 129, column 76): Unexpected 2, expected a name-starting character.
scs-0100-w1-flavor-naming-implementation-testing.md (line 36, column 8): Unexpected /, expected a name-starting character.
scs-0104-v1-standard-images.md (line 107, column 8): Unexpected /, expected a name-starting character.
scs-0200-v1-using-sonobuoy-for-kaas-conformance-tests.md (line 52, column 60): Unexpected /, expected a name-starting character.
scs-0300-v1-requirements-for-sso-identity-federation.md (line 247, column 10): Unexpected /, expected a name-starting character.
scs-0400-v1-status-page-create-decision.md (line 159, column 25): Unexpected /, expected a name-starting character.

For more details on these errors, please refer to the Upgrade Documentation.