doxygen: Added documentation for servo base and es08a

Signed-off-by: Kiveisha Yevgeniy <yevgeniy.kiveisha@intel.com>
cmake: added logic for building a tagged commit

* If the HEAD is 0 away from a tag, i.e. if it has just been tagged,
  removes commit number from version

Signed-off-by: Thomas Ingleby <thomas.c.ingleby@intel.com>