Migrate to DITA XML

- add DITA version of topics with no code
- add dedicated ditamap

Signed-off-by: Olivier Carrère <carrereo@gmail.com>
Acked-by: Angela Cristina <acristina@redaction-technique.org>
Remove reST files

Delete ReST files.

Signed-off-by: Olivier Carrère <carrereo@gmail.com>
Acked-by: Angela Cristina <acristina@redaction-technique.org>