Webatrice: improve prebuild steps and add .env configs (#4564)

* create .env file for server configuration

* render client version

* automate env file

* add prestart command

* create server-props.json instead of using .env

* automate master proto file

Co-authored-by: Jeremy Letto <jeremy.letto@datasite.com>

webclient/src/services/ServerProps.ts

@@ -0,0 +1,9 @@
+import props from '../server-props.json';
+
+class ServerProps {
+  get REACT_APP_VERSION() {
+    return props?.REACT_APP_VERSION;
+  }
+}
+
+export const serverProps = new ServerProps();

webclient/src/services/index.ts

@@ -1,2 +1,3 @@
 export * from './CardImporterService';
+export * from './ServerProps';
 export * from './dexie';