PubChem remaining tasks

[nesimtunc]

Per our conversation with @nesimtunc, here are the tasks that need to be done

• Create a table in the DB for keeping track of the imported/failed compounds.
• Use that table to rerun the script if the script crashes unexpectedly.
• Limit retry amounts for failed compounds.
• Create an endpoint to show the statistics, ie: the time to import a number of compounds, success/fail ratio, how many compounds are left to import
• Create a POST endpoint to trigger the import script with an authentication(token may be stored in .env) header with a JSON body that includes the startID and endID and an option to continue from the last compound
• Create a POST endpoint to trigger pause and stop the import script

Originally posted by @T410 in #16 (comment)