Repository API query signatures Entity free (#403)

* Migrated target management queries to IDs inetsead of full entities

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Added missing comment.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* refactored target,DS,cont,deploy,rg mangement.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Adde versioning documentation.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Rollout, Dist and Software mgmt refactored

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Readded line that was remove by incident. 

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Fixed broken tests.

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Query management refactored

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Fix bug of auto assign DS delete

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Switch to collection

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Fixed compile error

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Small glitches

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

* Fixed test after merge

Signed-off-by: kaizimmerm <kai.zimmermann@bosch-si.com>

hawkbit-ddi-api/README.md

@@ -1,7 +1,11 @@
-# Eclipse.IoT hawkBit - DDI API 
+# Eclipse.IoT hawkBit - Direct Device Integration API - Model and Resources
 
 The Direct Device Integration (DDI) API is used by devices for communicating with the HawkBit Update Server through HTTP. 
 
+# Version 1
+
+The model follows [semantic versioning](http://semver.org) with MAJOR version, i.e. breaking changes will result in a new MAJOR version.
+
 # Compile
 
 #### Build hawkbit-ddi-api