chore: various gherkin improvements for e2e tests

[aepfli]

This PR

• using gherkin auto binding as described in [flagd] change e2e test to use autobinding of gherkin test #986
• unify the location for the test harness, spec and the auto binding files within flagd-core instead of flagd and flagd-web
• removing file operations to move the feature files before execution into a seperate folder (no need for this anymore)
• removed step definitions and constants of e2e tests from the built package

Related Issues

Fixes #986

Follow-up Tasks

currently the path for the gherkin feature files is 'hardcoded' and not autmatically resolved relatively to the test (maybe somebody has a good idea for this)

[aepfli]

okay, i failed here hard, i did not check the api, and the webclient and the server client do not have an overlapping api - hence that part of this improvements are not worth it. eg. the normalization witthin flagd-core. I could generate an wrapper around it, to be passed on to the stepdefinitions, but imho i do not think that this is worth it.

[aepfli]

@beeme1mr @toddbaert I think this is ready. I just have had no time to investigate why the flags changed test for flagd-web is failing. If I find the time I will investigate. If you on the other hand read this, before my next message and have more insights (maybe not implement fully) just let me know ;)

[aepfli]

@beeme1mr @toddbaert I think this is ready. I just have had no time to investigate why the flags changed test for flagd-web is failing. If I find the time I will investigate. If you on the other hand read this, before my next message and have more insights (maybe not implement fully) just let me know ;)

Okay it seems like we are not providing a list of changed flags - as we are reloading all of them - makes sense. The question is, if it is worth checking if the flag has changed from previous calls. Or if getting the event alone is test enough

[toddbaert]

Will check this out tomorrow!

[toddbaert]

Amazing! I tested this locally a few ways, the right things are being tested and almost everything looks right.

A few minor nits I left where we are logging the wrong thing.

My only blocker is this.

[beeme1mr]

Looks good but please address the linting issues before merging. Nice job!

[toddbaert]

Amazing!