Task: Refactor Polling to use Mutation Observers

[alexmdodge]

The polling is working to determine when a specific page is loaded, but leaves a bit to be desired when responding to DOM change while loading content. Some ideas around improving this,

• [ ] Use mutation observers where appropriate to detect DOM changes and respond
• [ ] Load the explorer container first, while keeping the other file explorer views loading. This allows for better user experience and loading indication