Bump to systemdspawner 1.0.0 (not yet released), investigate how to handle sudo disabled by default

[consideRatio]

In https://github.com/jupyterhub/systemdspawner/pull/91 SystemdSpawner.disable_user_sudo was changed to default to True, which may be a breaking change we must consider.

Action points

• [x] Understand the current sudo permissions in tljh
• [x] Understand what sudo permissions we want for tljh 1.0.0 by default
• [x] Take action