Feature request: domainAllowList should be a configurable plugin setting

In order to support airgapped installations that run from local repositories domainAllowList should be a configurable plugin setting.

at

[domainAllowList ](https://github.com/coder/jetbrains-coder/blob/79118e354636b698e7e3b241f0a7c34a3a1a3ed2/src/main/kotlin/com/coder/gateway/util/LinkHandler.kt#L250
) 