add domain and subdomain for dev env (#1379)

## Description:

env variables DOMAIN and SUBDOMAIN were not found in the env, so have
DevServerConfig override the methods.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan

src/core/configuration/DevConfig.ts

@@ -34,6 +34,14 @@ export class DevServerConfig extends DefaultServerConfig {
   gitCommit(): string {
     return "DEV";
   }
+
+  domain(): string {
+    return "localhost";
+  }
+
+  subdomain(): string {
+    return "";
+  }
 }
 
 export class DevConfig extends DefaultConfig {