14240 extensibility ability to create multiple custom domains for each workspace 2 (#14307)

Adds a public-domain core-module. 
Reorganize custom-domain files properly

packages/twenty-server/src/engine/core-modules/twenty-config/config-variables.ts

@@ -892,6 +892,15 @@ export class ConfigVariables {
   @IsOptional()
   SERVER_URL = 'http://localhost:3000';
 
+  @ConfigVariablesMetadata({
+    group: ConfigVariablesGroup.ServerConfig,
+    description: 'Base URL for public domains',
+    type: ConfigVariableType.STRING,
+  })
+  @IsUrl({ require_tld: false, require_protocol: true })
+  @IsOptional()
+  PUBLIC_DOMAIN_URL: string;
+
   @ConfigVariablesMetadata({
     group: ConfigVariablesGroup.ServerConfig,
     isSensitive: true,
@@ -963,6 +972,15 @@ export class ConfigVariables {
   @ValidateIf((env) => env.CLOUDFLARE_API_KEY)
   CLOUDFLARE_ZONE_ID: string;
 
+  @ConfigVariablesMetadata({
+    group: ConfigVariablesGroup.ServerConfig,
+    description: 'Base URL for public domains',
+    type: ConfigVariableType.STRING,
+  })
+  @IsUrl({ require_tld: false, require_protocol: true })
+  @ValidateIf((env) => env.PUBLIC_DOMAIN_URL)
+  CLOUDFLARE_PUBLIC_DOMAIN_ZONE_ID: string;
+
   @ConfigVariablesMetadata({
     group: ConfigVariablesGroup.Other,
     description: 'Random string to validate queries from Cloudflare',