Layout format update: AddToToc, IsTocCaption, OutlinerName

Layout format update: AddToToc, IsTocCaption, OutlinerName

Preliminary work for addressing #7790. Thanks to Richard for providing initial
files this is based on.

Adding to TextClass:
    OutlinerName <string> <string>
    (the second string is translated)
e.g.:
    OutlinerName thm "Definitions & Theorems"

Adding to Layout:
    AddToToc <string>     (default "", means no)
    IsTocCaption <bool>   (default 0)
e.g.:
    AddToToc thm
    IsTocCaption 1

Adding to InsetLayout:
    AddToToc <string>     (default "", means no)
    IsTocCaption <bool>   (default 0)
e.g.:
    AddToToc literate

Adding to inset arguments:
    IsTocCaption <bool>   (default 0)