Parallelize updates / update checks

[emkll]

In #396, we've introduced a new way for users to apply workstation updates prior to running the client.

In its first iteration, this approach takes around ~3-5 minutes to check for updates, because the checks are performed sequentially. We should parallelize these checks for better performance, as the machine will likely not be used during that time. We can use most of the available resources available.

[emkll]

Closing, this is a duplicate of #403