[pgAdmin4] RM5965 Couldn't download file of Marcos query results

Hi Hackers,

Please find the attached patch which resolves the issue of macros query
results download, have used async cursor to achieve this functionality,
where for downloading the results, cursor is scrolled back to 0 and end of
the records, and reset again while user scrolling on Data Output table.

QA/Reviewer needs to observe below issues if it occurs:

1. If records are more like 5000 or 10000, try to fetch records by
scrolling at least (2000), now save the results by clicking the download
button, it should save the file, and now try scrolling again, the data
should be shown continuously and not any abrupt end or unexpected records
order.
2. Also, the download button is now "Save results to CSV/TXT" where it
will only get enabled when there are valid records in the Data Output.

Also a minor fix of the add folder icon issue is also added into this patch.

--
*Rahul Shirsat*
Senior Software Engineer | EnterpriseDB Corporation.