Support any version in Index.cshtml when replacing frontend version

[bjosttveit]

Description

This adds support for replacing any frontend version in Index.cshtml. Unfortunately, this was a bit more involved than expected, since the standard sub_filter only allows simple string substitution and not regex. To get around this, I needed the third-party ngx_http_substitutions_filter_module. This required some modifications to the standard docker image for nginx which I based on this.

This also fixes a bug where it would not find the frontendVersion cookie if it was the last one in the Cookies header. This is because it previously required the string to end with a ;. This probably explains the flakyness I myself have experienced with this before.

Related Issue(s)

• closes #77

Verification

• [x] Your code builds clean without any errors or warnings
• [x] Manual testing done (required)

[bjosttveit]

Sounds like a good idea to get rid of nginx @ivarne, this is indeed an overcomplicated way to do this 😅

Should I still merge this as a short term fix? And then maybe we should create an issue to look into rewriting the proxy feature?

[ivarne]

Should I still merge this as a short term fix?

Yes, That is what an approval with no positive comment means. If it works and is better than what we have, it is ready for merge.