[HALON-759] visualize-schema: Visualize relation cardinalities

[1468ca0b-2a64-4fb4-8e52-ea5806644b4c]

Created by: vvv

Use DOT arrow styles to represent cardinalities:

CardinalityFrom | CardinalityTo | arrowhead | arrowtail
----------------|---------------|-----------|----------
AtMostOne       | AtMostOne     | normal    | none
AtMostOne       | Unbounded     | onormal   | none
Unbounded       | AtMostOne     | normal    | oinv
Unbounded       | Unbounded     | onormal   | oinv

HA.Resources.TH:

• add cardinalities function;
• [refactoring] extract conTs function;
• [refactoring] use DecsQ and ExpQ aliases for the sake of uniformity.

[shailesh-vaidya]

Closing as an obsolete