Add KaTex supports for Editor

[ruibaby]

Currently, Halo 2.7 already supports the extension of the editor, now it's time to extend the KaTex input of the editor with this plugin.

Related documentation and issues:

• https://github.com/halo-sigs/richtext-editor/issues/14
• https://github.com/halo-sigs/richtext-editor/blob/main/docs/extension.md
• https://github.com/halo-dev/halo/blob/main/console/docs/extension-points/default-editor%E2%80%93extension.md
• https://docs.halo.run/developer-guide/plugin/hello-world

[ruibaby]

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