Make it possible to show any panel as disabled by default

[dmk23]

Right now only redirect panel could be shown disabled by default (via INTERCEPT_REDIRECTS panel option)

It should be possible to make any other panel display disabled by default, where it could be enabled (if needed) by one click instead of having to edit the config.

This is especially needed for resource-intensive panels (like Templates, SQL, Cache) which could cause massive slowdown on most pages.

[aaugustin]

Yes, it would make sense to deprecate INTERCEPT_REDIRECTS in favor of a new setting that would control whether each panel is enabled or disabled by default.