Page's `skip` option to be set at runtime

[nagyrobi]

Ability to change skip value at runtime in:

lvgl:
  pages:
    - id: page_remote_stuff
      skip: false

Maybe with something like:

    - lvgl.page.update:
        id: page_remote_stuff
        skip: true

Use case: to allow or disallow access to certain pages depending on requirements, like

• only show heating controls page during winter
• hide pages controlling remote entities while HA is down/rebooting
• ...