Change KoTextAnchor into three new classes
KoShapeAnchor - which in theory should be moved to flake later
KoAnchorInlineObject - which is the kotext part responsible for being an inline (asChar) object
KoAnchorTextRange - which is the kotext part resposible for toChar and toParagraph anchoring

Now the user no longer have to contend with invisible characters acting as anchors. These kinds
of anchors are now placed at a cursor position instead (using KoTextRange)

This also has the benefit that we can support toParagraph anchoring a bit better, as it's no
longer possible to move the anchor character away from the paragraphs first position.

REVIEW: 108459