Manage latch locking/unlocking

[qzed]

We currently have no direct support for managing the latch lock. To do this, we need some way to manage dependencies on the dGPU (or other devices connected to the base, e.g. USB/storage) either by applications or directly by the user. One idea would be to have some sort of registry of blockers/dependencies.

Ideally we have some automatism that detects and registers apps using the dGPU (or other devices connected to the base) automatically. That's probably not easily possible, so some sort of wrapper script may be necessary, at least for registration. For applications, de-registration could maybe be done automatically by monitoring process IDs for termination (may require special handling for sub-processes).

In light of Linux being a multi-user OS, it should also be possible for users themselves to request a lock on the base, preventing detachment until no user (and no application) has such a lock.

Furthermore, some UI for inspecting/displaying those dependencies that can be shown/linked to if a detachment request was blocked would be a good idea.