Testing: Docs and helper scripts

Description

Scripts and E2E spec changes

1. Add back remote dev scripts directory with helper scripts for smoke test and e2e
2. Tweaks to make E2E test work locally

MR: !120964 (merged)

Local Dev Setup Docs

1. Update local dev env setup docs to match latest code, and match E2E test var values

MR: gitlab-org/remote-development/gitlab-remote-development-docs!30 (merged)