Ability to add Pam entries in User vaults

Right now, storing privileged credentials requires creating a separate, dedicated "high" level vault for each user, on top of the regular user vault they already have. Being able to add PAM entries directly into the existing user vault would eliminate that duplication — no need to provision, name, and maintain a second vault per person just to hold their privileged accounts.

It also reduces ongoing admin overhead. Every time someone new needs privileged access, instead of standing up a brand-new vault and re-applying visibility, checkout, and rotation policies to it, the entries could simply be added to a vault that's already configured correctly. Fewer vaults overall also means less to audit and license-track, since policy sets wouldn't need to be duplicated across near-identical objects.