Improve the Sandbox when editing JSON

[charliehullmoonpig]

Is your feature request related to a problem? Please describe.
When using Elasticsearch or OpenSearch, we regularly work with very long JSON queries. Often we're only working with certain parts of this query, so we have to manually collapse parts of the tree every time we open the Sandbox. We can delete parts of the tree wholesale but there is no way to temporarily disable them, e.g. to take out a filter clause for testing.

Describe the solution you'd like
Each line of the editor should allow two extra functions:

• sticky collapse, so once it's collapsed it stays that way until we un-stick it
• mute, so once it's muted it's temporarily removed from the query sent to the engine.
  This would allow (for example) a 'filter' clause in ES/OS DSL to be collapsed for readability and optionally temporarily removed to see what happens when filters are not applied.
  I'm unsure how this would interact with Tries, but perhaps each Try could record the collapsed/.muted clauses somehow. Collapsed and muted clauses should be very obvious in the UI (perhaps an arrow showing there are muted clauses above/below the current view).