Update All action
### Current Situation

Right now it's a bit annoying to have to go through multiple phases of updating Homebridge (core, then UI, then each plugin individually) and then restarting Homebridge each time.

### Proposed Change

An "update all" button that runs the npm update process for all things pending updates simultaneously, possibly adding a separate "hold version" function to individual plugins that the user does not want to be mass-updated in this way for some reason.

### Additional Context

Since these are all NPM packages it seems like it should be possible to just update everything all at once, right?