Haddocks command

By passing `--haddock-html-location` one can link to haddocks to
documentation published on hackage.  However one can use it or
`--base-url`.  The latter will build self contained directory of haddock
documentation.

It is supported at least from `haddock-2.16`.

Generated haddocks will have valid links to packages distributed with
GHC, e.g. `base`, `bytestring`, `array`, etc.

Haddock-2.26.1 allows to configure whether modules from a given interface
file should be visible on the generated content page.  We make visible
only modules which come from local packages.

It was broken in various ways :/

* The CmdHaddock (and CmdHaddockProject) have to restore the paths set with
  'haddockProgramPath' (or 'haddockProjectProgramPath');
* haddock is not by default in 'ProgramDb'; We need to add it first,
  otherwise 'reconfigure' will not update its path.
* 'setupHsHaddockFlags', need to store haddock location in
  'haddockProgramPaths.

This patch also adds 'haddockProjectProgramPath' and
'haddockProjectProgramArgs' to 'HaddockProjectFlags' which are passed to
'CmdHaddockProject'.

This allows to test against a newer version of haddock than one that
comes with `ghc`, even with head of `haddock` repository.

The 'haddock-project' command can be used to create haddocks of all
components together with indexes (html, quickjump) and the content page.

Added arguments:
* 'argGenContents': haddocks' '--gen-contents'
* 'argGenIndex': haddocks' '--gen-index'
* 'argPrologueFile': haddocks' '--prologue' but unlike '--argPrlogue' it
  passes the file name not the prologue text itself.

We need 'renderArgs' to work when we create an index. In this case some
of the options will not be set.

This is useful for passing arguments to `haddock-project` command which
will create haddocks for all the components, together with a consistent
index.

Added:

* `haddockIndex`: passed as '--use-index' to 'haddock'
* `haddockBaseUrl` : passed as '--base-url' to haddock'

Drop >= in suggestions to cabal-version (rebase #7104)

Co-authored-by: Jeremy Scott <jeremy@jeremyscott.io>
Co-authored-by: Artem Pelenitsyn <a.pelenitsyn@gmail.com>
Co-authored-by: Francesco Gazzetta <fgaz@fgaz.me>

docs: allow TOC navigation

fix warnings: update extlinks format to Sphinx 5

bootstrap: generate missing Setup.hs in dependencies

This allows bootstrapping against zlib 0.6.3.0, which ships
without Setup.hs.

I hope this should generally be a more robust approach than
asking maintainers of dependencies to keep Setup.hs.

Remove Cabal version check that applied to already not supported <1.19.2

We used to check that, under presence of --allow-newer/older, Cabal version is >=1.19.2 (earlier versions don't get these flags), but we no longer support <.1.19.2 anyway, so the check is not needed. Remove.

Exclude broken 'Validate windows-latest ghc-8.6.5' job that cancels CI

* Fix cabal exec extension for win

* Use tabs in the changed region

* Use exe ext when zipping

* Apply suggestions from code review

Co-authored-by: Robert <rob@vllmrt.net>

* Add curly braces to var

Co-authored-by: Robert <rob@vllmrt.net>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

docs: move Configuration chapter to cabal-install reference

There was nothing about installing packages in this file for a while now.

Improve documentation formatting of some cabal command flags

Use proper option formatting instead of bullet points.