Bug 8745: Migrate EditConfig to the new XML parser

Bug 8745: Migrate EditConfig to the new XML parser

Switch EditConfig class to use the new XML parser from YANG tools.

Introduce EditOperationNormalizedNodeStreamWriter as a replacement
of the old XML parser extension EditOperationStrategyProvider which
has been used for tracking edit-config data tree operations defined
in the parsed XML source.

Remove EditOperationStrategyProvider as it is not needed anymore.

Change-Id: I737b134805120368a352568fde3f19517a9871df
Signed-off-by: Igor Foltin <igor.foltin@pantheon.tech>