Change (disabled) to (uninstalled) on Modules and Themes pages

Problem/Motivation

It was decided to use "install" instead of "enable" for modules and themes in #3162049: [meta] Better wording of the module life-cycle admin pages. See also:

• #2888657: [meta] Less confusing and more consistent wording needed in module/theme add/install/update
• Modules cannot be in a disabled state anymore, only installed and uninstalled

But modules in the list of modules that are not installed on the "Extend" page (/admin/modules) use the suffix "disabled", in parentheses.

"Uninstalled themes" is used on the "Appearance" page (/admin/appearance) and "uninstalled" in #3611590: Use Installed and Uninstalled on Available updates page, so we should probably use that to stay consistent, rather than for example "not installed".

"disabled" is also used in the text under an uninstalled theme, so also needs an update.

Steps to reproduce

See the list of Modules under /admin/modules ("Extend") use the suffix "(disabled)", even though we install and uninstall modules, not enable/disable as in Drupal 7.

Proposed resolution

To be consistent, the suffix should probably be "(uninstalled)".

We could do this for both modules and themes.

Remaining tasks

Update the relevant files and tests for modules and themes to use "(uninstalled)", and not "(disabled)".

User interface changes

Modules that are not installed will use the suffix "(uninstalled)" on the "Extend" page (/admin/modules).

Introduced terminology

API changes

Data model changes

Release notes snippet