Fix disk setup and documentation for Turnkey VMs

[havardthom]

Note

We are meticulous when it comes to merging code into the main branch, so please understand that we may reject pull requests that do not meet the project's standards. It's never personal. Also, game-related scripts have a lower chance of being merged.

Description

Turnkey VM scripts have only had a bootdisk with ISO image, so people had to figure out themselves that another disk must be added to partition and install OS on. This issue caused Tteck to remove docs until more testing had been done: tteck/Proxmox#2351 (reply in thread)

This PR

• Fixes Turnkey VM scripts by adding another disk for OS installation
• Adds back documentation for Turnkey Nextcloud VM
• Fixes documentation for Turnkey ownCloud VM
• Fixes documentation for Jellyfin (crashes in production atm)
• Changes unique script identifier in frontend from name to slug, because name is not unique (we have both Nextcloud VM and LXC). This will be a breaking change for id param in URL (if anyone have a script bookmarked), but it's better to do this change as early as possible. slug should always be unique since it is the same as script filename.

I am also planning on creating a Turnkey VM Install Guide in Github discussions to reference in documentation, since those VMs require a bootdisk installation process.

Fixes #93
Fixes tteck/Proxmox#2351 (reply in thread)

Type of change

Please check the relevant option(s):

• Bug fix (non-breaking change that resolves an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (a fix or feature that would cause existing functionality to change unexpectedly)
• New script (a fully functional and thoroughly tested script or set of scripts.)
• Documentation update required (this change requires an update to the documentation)

Prerequisites

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• Self-review performed (I have reviewed my code, ensuring it follows established patterns and conventions)
• Testing performed (I have tested my changes, ensuring everything works as expected)

Additional Information (optional)

Provide any additional context or screenshots about the feature or fix here.

[MickLesk]

Looks okay for me

[BramSuurdje]

LGTM