Started refactoring IDocumentContentOperations out of SwDoc.

The work all done except for moving all calls to the interface's functions
from SwDoc::.. to SwDoc::getIDocumentContentOperations::..
I didnt do that yet in case we make some design change.

Things I had to change that are not simply refactoring:

Made SwNodes in sw/inc/ndarr.hxx friend class to
DocumentContentOperationsManager so it can call DelNodes at end of
DocumentContentOperationsManager::DeleteSection .

I put all local functions in the Manager in anonymous namespaces.

Added DeleteAutoCorrExceptWord to SwDoc, its needed in the Manager.

Added a non const version of SwDoc::GetDfltGrfFmtColl() to SwDoc
because its needed in the Manager.

Had to make SwDoc::checkRedlining and SwDoc::_MakeFlySection public
because they are both used in the Manager and SwDoc internal places.

Had to make SwDoc::CopyImpl_ public because it is used in the Manager.
Even though it is only used in the manager, moving it there is not
trivial because it uses many local functions in ndcopy.cxx that would
have to be copied as they are used in both places.
Also DocumentContentOperationsManager::CopyRange calls CopyImpl on a
different SwDoc (not the one that owns the calling manager) so it
needs to be public for that too.
Maybe there should be a manager of some sort to hold the many copy
functions and the local helpers...

Had to duplicate "struct ParaRstFmt" and "lcl_RstTxtAttr" from docfmt.cxx
in DocumentContentOperationsManager.cxx because they are used in both files.

Other things I noticed:

Some methods are private in the Manager because they were so in SwDoc,
but they are only used there and might as well be local functions.
Why are they private and not local?

Why are sw_GetJoinFlags and sw_JoinText apparently global functions
defined in docedt.cxx . It looks like they should be moved somewhere.
They are only used in this Manager and one other place.

UpdateParRsid and UpdateRsid where grouped under
IDocumentContentOperations in SwDoc but  are not part of the interface.

Change-Id: Icaab57f4a8c158a85e549ecb4aacc752bc95bbc9