split hardware page into multiple page

This is an example.
link section example
Cards : new toctree
Cards : page rewritten. This page explain how to create the
dahdi/modules file and how to select the line mode between E1 and T1.
Typo
Add ref
Cards EC : page rewritten with new organization
Harmonize structure with echo_canceller page
Fix a typo
Corrections following a re-reading of the pages
Typo in next step
HWEC configuration re-reading
Add introduction before the toctree
Interconnection : add configuration details for custom interconnection.
Specifically, add details for DAHDI interco.
This commit include a short description of dahdi-channels.conf file.
Rewrite BRI card configuration section.
The specific configuration paragraph is not written yet.
Change typo
Correct a mistake. Add a 'you may' in the specific paragraph
Rewrite PRI card configuration page.
BRI configuration : add the 3 recommended configurations
Remove spaces in empty lines