* supports overriding the replayweb.page version without having to be rebuild frontend image:
- ensures 'rwp_base_url' from helm chart is passed to nginx
- ensures both ui.js and sw.js are loaded based on nginx environment variable, not hard-coded
- ui.js loaded via redirect from new /replay/ui.js path
- pin RWP to known working release in default values.yaml
- remove RWP_BASE_URL from Dockerfile, no longer needed, set via chart env var
- set default RWP_BASE_URL for devserver to use CDN
- set RWP version to 1.8.11