Split configuration into low and high traffic files

Also, we're now handling config ourselves instead of using
electron-config and config dependencies.

app/ephemeral_config.js

@@ -0,0 +1,12 @@
+const path = require('path');
+
+const { app } = require('electron');
+
+const { start } = require('./base_config');
+
+const userDataPath = app.getPath('userData');
+const targetPath = path.join(userDataPath, 'ephemeral.json');
+
+const ephemeralConfig = start('ephemeral', targetPath);
+
+module.exports = ephemeralConfig;