Some Python class and packages need to be renamed
for a better compliance with the shared terminology
which provides a better understanding of Watcher
objects and components by every contributor.
This patchset is there to change
Primitive to Primitives.
Add BasePrimitive.
Partially implements: blueprint glossary-related-refactoring
Change-Id: I839bddd12b5320b338b2f207d74963afa23de522
