DOC: Transfer the wiki FAQ page to Markdown documentation

Transfer the wiki FAQ page to Markdown documentation:
https://itk.org/Wiki/ITK/FAQ

Add the corresponding entry in the `Learn` section of the documentation
index.

Take advantage of the transition to:
- Update URLs, including changing `http` to `https`, fixing broken URLs,
  etc.
- Link ITK and VTK classes to their Doxygen documentation pages.
- Highlight parts (e.g. class names) using Markdown syntax.
- Make the BibTeX list style consistent, remove broken URLs pointing to
  old versions of the SW Guide or all pointing to the latest PDF
  available online, etc.
- Remove outdated paragraph about libraries to build visualization
  applications.
- Change mentions to `ImageViewer` to `itkwidgets`.
- Prefer pointing to the Python `imageio` package over `ImageMagick`.
- Mention `itk-wasm dicom` to read a volume from a DICOM series.
- Reword the language binding section: remove Java and mention that
  further bindings are available through SimpleITK and itk-wasm.
- Remove the `What does \`Error opening hint file NOTFOUND\` mean?`
  section.
- Remove the language binding/wrapping section, as it is outdated: it
  refers to the current SWIG wrapping before it was integrated into the
  ITK repository.
- Remove mentions to section number and pages in the ITK SW Guide, as
  they have changed and may change in the future.
- Remove the emacs coding style section.
- Rewrite the Vim coding style section, as ITK's coding style is now
  enforced and/or checked automatically, and as ITK switched from
  `txx` to `hxx` suffices some time ago.
- Remove the empty `What is the `\`ITK_TEMPLATE_VISIBILITY_DEFAULT\`
  CMake option?` section.
- Remove the outdated `Platform-specific questions`section.
- Fix typos and grammar, and reword passages for better understanding.
- Change the title to `Frequenty asked questions`.

Documentation/docs/index.md

@@ -30,6 +30,7 @@ download
 Examples <https://examples.itk.org>
 Tutorial <https://github.com/InsightSoftwareConsortium/ScientificImageAnalysisVisualizationAndArtificialIntelligenceCourse>
 Software Guide <https://itk.org/ItkSoftwareGuide.pdf>
+learn/faq.md
 learn/courses.md
 ```