[Test] increase e2e test confidence

[oversparkling]

Problem

Closes #2124

Features:

• Increases code confidence of our repository, especially our virus scanner on files

Noticable changes from this PR

• Local E2E tests may fail locally if there is a urls.csv lurking in downloads folder
• Changes made to docker-compose will require a .env file to be present in local directory (KIV on this approach atm)

Tests

What tests should be run to confirm functionality?
Contribution to E2E Tests

[gweiying]

Noting that above tests addresses these test cases:

User page

• Ellipses are shown for very long links

URL creation

• It should prevent uploading when a malicious file is submitted

URL Searching and Download (?)

• Clicking on the download button downloads all links currently shown in the links table as a .csv file.

User page - Sort & Filter

• Links should be sorted by their number of clicks in descending order when enabling sort by Most number of visits and clicking apply

[oversparkling]

Referencing this, we removed empty variables from being assigned in docker-compose so that it defaults to .env file that is created during CI.

[gweiying]

lgtm!