Turn the "select a config" button into a drop down list with view templates

As suggested by @nvictus:

Current the `select a config` file selection button is confusing as it looks like a drop down button.

Instead it should open a drop down which lets the user select between choosing either a predefined view config if different layouts and an option to load one's own view config

The templates could include
- 2 column
- 3 column
- etc.

No files or tests are identified. Locate the frontend entry point for the current “select a config” button, then review how view configurations are loaded and displayed. Done means the control presents predefined view templates such as two- and three-column layouts alongside an option to load a custom view config.

Written by the indexing model from the issue text.