BUILD/MEDIUM: deviceatlas: updating the addon part.

BUILD/MEDIUM: deviceatlas: updating the addon part.

- Reflecing the changes done in addons/deviceatlas/Makefile.inc.
 Enabling the cache feature and its disabling option as well.
- Now the `dadwsch` application is part of the API's package for more
general purposes, we remove it.
- Minor and transparent to user changes into da.c's workflow, also
making more noticeable some notices with appropriate logging levels.
- Adding support for the new `deviceatlas-cache-size` config keyword,
 a no-op when the cache support is disabled.
- Adding missing compilation units and relevant api updates to
the dummy library version.