Export TSVB related objects

[abbanabennanih]

Describe the feature:
Add the ability to export TSVB related objects. For example, export the index-pattern 'my-index-pattern' when exporting TSVB object. The feature already exists for the most Kibana objects except TSVB.

Describe a specific use case for the feature:
It's a classic use case where we need to develop some dashboards on dev env and then export/import them into Production env.

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[flash1293]

That's a valid request - it doesn't work right now because TSVB is not using index pattern saved objects but stores the string directly. However we are already planning to migrate TSVB to use index patterns: #91367