feat: e2e tests

[alexey-yarmosh]

Fixes #47

Local run of e2e tests from that repo was not added, as it would add a lot of mess to support editable local env vars (e.g. specifying DIRECTUS_URL=http://localhost:18055 instead of DIRECTUS_URL=http://127.0.0.1:18055).
Tests still can be executed locally from https://github.com/jsdelivr/globalping-dash-directus. Since those 2 repos always goes hand in hand, I think that is ok to run e2e tests from there. That PR adds execution on CI.

[MartinKolarik]

So when working on something just in this repo, to run the test, we'd have to push the changes, create a matching branch in the other repo, and then run it from there? Can't we do something like in the probe repo, where config files with 2e2 in the name are copied to the image?

[alexey-yarmosh]

So when working on something just in this repo, to run the test, we'd have to push the changes, create a matching branch in the other repo, and then run it from there?

If your version of globalping-dash is already running on port 13010, it will be used by e2e tests, without starting a new instance. So you can just run e2e tests from master branch of globalping-dash-directus.

Can't we do something like in the probe repo, where config files with e2e in the name are copied to the image?

We can, but in requires at least 2 .env files, to update .env and .env.e2e respectively. Also when e2e test fails you most likely want to debug and run tests with browser window. And e.g. my IDE extension can't find test files hidden in test/e2e/globalping-dash-directus subdirectory. So I'll go to globalping-dash-directus and execute from there anyway.

It will also require some updates to the init scripts, to support .env files override, and I am not sure all that complications will make e2e tests easier to run.

[MartinKolarik]

If your version of globalping-dash is already running on port 13010, it will be used by e2e tests, without starting a new instance. So you can just run e2e tests from master branch of globalping-dash-directus.

Ok that seems fine then, just document it later in #53.