We rename this helper along the config types & helper types for it
because the word "page" is used more often in the context of paging
through results using an offset and limit whereas this helper is
specifically used to split up the slice in queries of the form
"WHERE x in []slice". We do this rename so that there is mimimal
confusion in contexts where we use batching along with actual paging.
The config struct is also renamed to QueryConfig in preparation for it
holding more config options.
This commit adds a helper test that is similar to TestPopulateDBs except
for the fact that it uses the MigrateGraphToSQL function directly to
migrate a local kvdb-sql graph to a native SQL one.
This is a prep commit that just adds all the boilerplate connection
logic for connecting to various graph DBs. These will be used in
upcoming commits which will add tests and benchmarks.
