Fix hub image dependency versions, disable ltiauthenticator, use chartpress==0.5.0

[consideRatio]

Fixes #1501, again.

• By specifying jupyterhub-kubespawner==0.11 we actually pinned it to 0.11.0 where I assumed it would be considered to mean 0.11.* as conda behaves. That was a faulty assumption that is now corrected.
• Bumping chartpress just to stay up to date.
• Disabling ltiauthenticator because it is incompatible with current JupyterHub that depends on oauthlib>=3.0 while ltiauthenticator requires 0.2 and crashes on >=0.3. I may have fixed that upstream in ltiauthenticator with some currently unmerged PRs. See https://github.com/jupyterhub/ltiauthenticator/pulls and Bump oauthlib dependency ltiauthenticator#24 specifically.