Make Flask-Minify opt-in

* it looks like the extension may have been linked with issues regarding
  user-related operations such as login and file upload, so we decided
  to make it opt-in for now

invenio_config_tuw/config.py

@@ -52,6 +52,9 @@ CONFIG_TUW_READ_ONLY_MODE = False
 CONFIG_TUW_DISABLE_ERROR_MAILS = False
 """Disable registration of the SMTP mail handler to suppress warnings."""
 
+CONFIG_TUW_MINIFY_ENABLED = False
+"""Enable or disable the Flask-Minify extension."""
+
 
 # Invenio-Mail
 # ============

invenio_config_tuw/ext.py

@@ -78,7 +78,12 @@ class InvenioConfigTUW(object):
                 app.config[key] = app.config["DATACITE_USERNAME"]
 
     def init_minify(self, app):
-        """Initialize the Flask-Minify extension."""
-        if "flask-minify" not in app.extensions:
+        """Initialize the Flask-Minify extension.
+
+        It seems like this extension may cause issues with certain user-related
+        operations in the system and has thus been disabled by default.
+        """
+        minify_enabled = app.config.get("CONFIG_TUW_MINIFY_ENABLED", False)
+        if minify_enabled and "flask-minify" not in app.extensions:
             minify = Minify(app, static=False, go=False)
             app.extensions["flask-minify"] = minify