Flesh out bounded string / bounded sequence handling in IDL import:

umbrello/codeimport/idlimport.h
- Add member m_doc of type UMLDoc* for conventiently accessing
  UMLApp::app()->document().

umbrello/codeimport/idlimport.cpp
- In constructor initialize m_doc.
- In function parseStmt keyword "typedef" handling of template types :
  - In case of «idlSequence» create newType as Class instead of as
    Datatype.  Reason: Umbrello does not currently support the menus and
    dialogs for adding/manipulating attributes of UMLDatatype.
  - Implement «idlSequence» / «idlString» stereotype attribute "bound"
    of type Uml::PrimitiveTypes::UnlimitedNatural.
    When applying «idlSequence», if the concrete tag value provided in
    UMLObject::tags() is empty then this means it is an unbounded
    sequence.
  - In case of «idlSequence» create an attribute "members" on newType.
    The type of the attribute is the origin type of the typedef (i.e.
    oldType).
  - Set the calculated stereotype on the newType object.
  - Append the extracted bound onto the tags() of the new type object.

CCBUG: 81301