Add inverted egg and YZ as cross section shapes

[leendertvanwolfswinkel]

Has been implemented in threedigrid-builder; when it has been added to threedi-modelchecker and tested, it can also be implemented here.

[caspervdw]

See here for the modelchecker implementation: https://github.com/nens/threedi-modelchecker/pull/239

[leendertvanwolfswinkel]

• [x] Add 7: "YZ" to the mapping for cross_section_shape of the layers Weir, Orifice, Culvert, Pipe and Cross section location
• [x] Add 8: "Inverted egg" to the mapping for cross_section_shape of the layers Weir, Orifice, Culvert, Pipe and Cross section location
• [x] Depending on the selected shape, some widgets (and their labels and X buttons) should be enabled / disabled. The following list shows the widgets that should be enabled for these new shapes:
• YZ: Table
• Inverted egg: Width
• [x] #90
• [x] Importing/exporting YZ profiles to sqlite will be more complicated than the inverted egg shape. See https://github.com/nens/threedi-schematisation-editor/issues/91 for more details