packaging - Add auto-pinning feature for packages with self-updaters

As discussed in issue #1573, consider the addition of a method for packages to be marked as self-updating software (programs that have a built-in auto-update feature), and auto-pin those packages to prevent sync issues between what Chocolatey thinks is installed and what is actually installed. This could be done by the package creators/maintainers or perhaps even by users via flagging them (though obviously in a way that would prevent a few users from incorrectly doing so).

Start by reading issue #1573 and the discussion here to understand the proposed self-updater marking and auto-pinning behavior. Before implementation, define whether package maintainers or users can flag packages, how incorrect flags are prevented, and what synchronization outcome is considered done.

Written by the indexing model from the issue text.