Bug 5730 - Delete subset of list items using PATCH?

Bug 5730 - Delete subset of list items using PATCH?

- fix: edit is not ignored when end of input is reached
- fix: only create, merge, replace and insert operations require value to be present
- fix: if value is not present with create, merge, replace or insert operation then error 400 is returned
- fix: if value is used with other operations error 400 is returned
- fix: deleting sublist values instead of full parent
- fix: order of patch edit fields is not important anymore (target, value)
- move class StringModuleInstanceIdentifierCodec to own file

Change-Id: I4c3f407858034b49795034da6c93b41f9d891b62
Signed-off-by: Ivan Hrasko <ivan.hrasko@pantheon.tech>