Migrate developer's guide to the cookbook

Summary

Migrate "Developer's guide" chapter to the CookBook. See what it looks like here.

Feedback welcome!

Rationale

Part of #1679

Implementation Details

• No changes in otb-data
• Migration was done with a script (migrate_sg_tex.py) based on regex + pandoc + manual review of the output
• Enable sphinx's extlink extension for doxygen links

In rst, automatic links to a doxygen class, an application or an example with:

the class :doxygen:`Image` is used for
the application :ref:`BundleToPerfectSensor` is
see example :ref:`ApplicationExample.cxx` for more

Copyright

The copyright owner is CNES and has signed the ORFEO ToolBox Contributor License Agreement.

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Check before merging:

• All discussions are resolved
• At least 2 votes from core developers, no vote.
• The feature branch is (reasonably) up-to-date with the base branch
• Dashboard is green
• Copyright owner has signed the ORFEO ToolBox Contributor License Agreement