- Also add documentation to CHANGES

FIXES #1343
FIXES #1319

- Groups inherit slightly differently: if a subgroup **explicitly**
  configures criticalness, use that. It would be weird, but possibly,
  to have a non-critical subgroup of a critical group.

- Use convenience predicate isPackage()
- Name child->item(i) for brevity

- An unselected group with (some) selected subgroups was not
  displayed as (semi)checked -- it was unchecked, because
  its checked-ness was not updated based on the children.

- An immutable group doesn't show a checkbox at all

- The section can't be changed, but is selected (it doesn't
  make sense otherwise)

- move ready-indication to Config
- don't check pointers that can't be null
- hand the whole Config to the page

- Create a config object in the ViewStep
- Model lives in the config object and loads there
- Give model to the UI page for display

- Netinstall doesn't make any jobs itself, so drop the member variable
- Use type alias, and simplify jobs()

- Since we might change translations after loading, display
  the message based on the status enum, rather than
  setting it once at load-time.

[partition] Increase Manual Partition instructions

- Remove commented-out code
- Fix layout
- Update to modern CMake approach

- Include order
- ci/calamaresstyle
- modern alias for job-list

- Mention that the sidebar menu can't be styled
- Point to more documentation about styling
- Give an example of styling buttons with an icon

used downstream since 2014, has helped a lot with increaisng correct setups

Merge upstream

FIXES #1352

- the `parent` when installing a translator was not used, so drop it
  from the API. Chase some uses of the API, but leave welcome-modules
   broken: there's a merge of those coming.

FIXES #1353

- It's the perennial struggle between Qt index types and STL ones

- ci/calamaresstyle
- sort includes by kind (local module, Calamares, Qt, STL)
- add copyright line

FIXES #1354
FIXES #1339

Might be a bit annoying, so there's a TODO to detect yes-i-already-have-
GPT-on-this-BIOS-system.