First sketch of a deepcopy between tiled instances

[danielballan]

This is enables workflows like databroker-pack but for Tiled.

from tiled.client.copy import deepcopy
from tiled.queries import KeysFilter
from tiled.client import from_uri
from tiled.client import simple

# Start a local server (in thread).
d = simple("data_dir")

# Connect to remote production server.
c = from_uri('https://tiled.nsls2.bnl.gov')

# Query for dataset(s) of interest --- just one in this example, but could be more.
r = c['bmm/migration'].search(KeysFilter(['f8c83910-4adb-4207-a465-9ff0ff0e9cd2']))

# Copy metadata and data from remote to local server.
deepcopy(r, d)

Checklist

• Add a Changelog entry
• Add the ticket number which this PR closes to the comment section