Code refactoring - Watcher Applier package

This patchset is there to change the code structure.
The objective is to flatten the project file tree by merging
'api/' and 'framework/' into a single package. This also contains
some tidy ups in package naming (like using only singular nouns).

This should only affect file/folder names and their subsequent
import paths wherever they were used.

Change-Id: Id7b37667c613086d8ef3cd1f367c4219bf026fc7

watcher/opts.py

@@ -16,7 +16,7 @@
 # limitations under the License.
 
 import watcher.api.app
-from watcher.applier.framework import manager_applier
+from watcher.applier import manager_applier
 from watcher.decision_engine import manager
 from watcher.decision_engine.strategy.selector import default \
     as strategy_selector