feat(ls): add AsyncAPI 3 completion for compatible keywords

[glowcloud]

This PR:

• adds AsyncAPI 3 completion for keywords compatible with AsyncAPI 2
• adds targetSpecs to every completion rule to apply them to select AsyncAPI versions
• moves AsyncAPI 3 parser adapter JSON detection to happen before YAML detection like for other parser adapters - otherwise JSON specs would be detected as YAML and in case of completion the result would be inserting YAML instead of JSON, e.g. channels: instead of "channels": { }