Everything else stays in esc.c

Also add a lot of code for reading the ESCs eeprom with configuration
parameters. Also provide 'struct esc_device' for generic device creation
and handling based on the eeprom configuration.

The el1xxx, el2xxx and el3xxx now use this generic device.
Also the el3xxx module now properly supports the EL3102 device.

Add comments to command_server lib
Remove now obsolete ec_el_test
Fix controller_sample shell newlines

Also some changes to properly log to console when no slaves are found

A few improvements from the Vitsch Electronics CVS
Use log_send() for all logging and add context (DEBUG/WARNING/ERROR) info.
A little bit more comments

Mostly ethercat related in the ec directory.