test(routes/login): add initial tests via supertest

[pano9000]

this PR adds some initial, basic tests for the login route — it does not cover every case yet, but we have a start now at least

[github-actions]

Folder/File	Previous size	New size	Difference
/upload/TriliumNextNotes-Server-1711-merge-linux-x64.tar.xz		85.17MB	+85.17MB (+100.00%)
TOTAL			+85.17MB

[github-actions]

Folder/File	Previous size	New size	Difference
/upload/TriliumNextNotes-1711-merge-linux-x64.deb		137.77MB	+137.77MB (+100.00%)
/upload/TriliumNextNotes-1711-merge-linux-x64.flatpak		130.87MB	+130.87MB (+100.00%)
/upload/TriliumNextNotes-1711-merge-linux-x64.rpm		145.79MB	+145.79MB (+100.00%)
/upload/TriliumNextNotes-1711-merge-linux-x64.zip		176.7MB	+176.7MB (+100.00%)
TOTAL			+591.13MB

[pano9000]

(tests currently fail of course, as long as the other "login" related PRs are not merged)

[pano9000]

hmm, the test is failing in CI with

⎯⎯⎯⎯⎯⎯⎯ Failed Tests 1 ⎯⎯⎯⎯⎯⎯⎯

 FAIL  src/routes/login.spec.ts > Login Route test > does not set Expires, when 'Remember Me' is not ticked
Error: Test timed out in 5000ms.
If this is a long-running test, pass a timeout value as the last argument or configure it globally with "testTimeout".
⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/1]⎯

but runs through perfectly fine locally.

will need to have a closer look this evening again