Clean up key list
Among others:
- Rename machine_manage_keys files to machine_keys
- Remove TagTextField
- Fix isScrolledToBottom function
- Remove deprecated functions from backends controller
- Fix image star toggle
- Move upload key function to keyAddController
- Scroll to top when opening create machine popup
- Fix backend state toggle
- Rename default_key property of key model to isDefault
- Make sure private key popup closes ONLY from the back button
- Better event listeners configuration for each view
- Fix image list view scrolling
- Fix python views for keys and backends
- Overal code pretification