Evaluate observed strapi import plugin issues

* Find out why import takes long time for synapses and what we can do to improve it
* We should display a loading spinner during analyze, the action can take quite some time and the user needs feedback to know if it's still running

@afonsobspinto please extend by what you could already find out

No files or tests are named. Locate the Strapi import plugin's analyze and import entry points, then measure why synapse imports take a long time and determine where progress feedback belongs. Done means documenting the findings and providing a loading spinner while analysis runs.

Written by the indexing model from the issue text.