privilege elevation

[rsteube]

Request

Some completions need elevated privileges (sudo, run0).
There's a whole load of issues with this:

• security (!)
• files/folders created with different owner as side-effect
• authentication
• remote invocation

Proposed solution

Maybe add something like Action.Elevate(user) to add an indicator to Context (ENV for compability?).
Then have a detached mechanism for privelege elevation (be it sudo, run0, or whatever).
Might work for commands will break any core os related functions.

Anything else?

related carapace-sh/carapace-bin#2708