Provide more context in error messages

[ci skip]

Add unit tests for the `MessageUtils` module in the cabal-install-solver package.

Fail reason now includes suggestions for misspelled language extensions
and language standard.

Add changelog entry for #7250

Fix #7460

standalone tests for `cabal init`

Print error message if no freeze file can be found

Prefer ProjectFlags over additional field in OutdatedFlags

Since most commands use 'ProjectFlags' but almost all commands can not
function properly without a project context, some commands manually
strip the flag '-z' (--ignore-project) from the command line option parser.

Unify the behaviour for all commands.

Allow relative paths starting with single-character directories

Add changelog for #7413 (Fix instantiating an indefinite Backpack from Hackage with an inplace package)

Modernise `outdated` command

Reformat imports and data declarations.
Remove old code-paths from `cabal-install/src/Distribution/Client/Setup.hs`
Remove unnecessary parentheses.
Mirror command structure from other Commands.

Cabal outdated should not list deprecated versions