App should auto-load raster after user has selected a file

[DanielJDufour]

Is your feature request related to a problem? Please describe.

• Annoying for users that they have to click load
• Maybe also shouldn't wipe away loaded file if a user clicks enter after loading the file

Describe the solution you'd like

• Autoload the file after a user has selected it or auto-select (move focus) to the load button after a user has selected a file, so that if they press enter if will load it

Describe alternatives you've considered

Additional context