SEARCH improvements

[carpawell]

Is your feature request related to a problem? Please describe.

I'm always frustrated when SEARCH is slow and really unoptimal.

Describe the solution you'd like

Improvements to consider:

1. Do not accumulate SEARCH results from local/remote storages in memory before streaming results, stream them immediately to make search a more flexible operation instead;
2. Return results sorted
3. ...

Describe alternatives you've considered

-

Additional context

nspcc-dev/neo-go#3645
nspcc-dev/neo-go#3647
#2721

[roman-khimov]

Sorted results can be merged by the intermediate node more easily, not requiring to wait for full result transfer. It changes the protocol semantically, but it's compatible as per binary protocol. Local results can also be returned in chunks, not waiting to accumulate the full reply.