Add support for tiptap v2

[JuroOravec]

I tried using tiptap v2 extensions, specifically StarterKit, but currently tiptap-vuetify uses tiptap v1, which is incompatible with v2 extensions.

Migrating would require:

• Change tiptap imports from tiptap to @tiptap/core.
• Change tiptap extensions import from tiptap-extensions to @tiptap/{extension-name}
• Possibly updating the extensions in nativeExtensions folder
• Maybe something more? Don't know.

@iliyaZelenko Is this planned for this project? If so, when?