[UI] Support for SHACL Node Expressions

[edmondchuc]

Add support for node expressions, a feature that allows dynamic calculations and selections within the user interface.

Node expressions can be used to:

• Calculate values within forms
• Select user-interface widgets
• Selection mechanism for other user-interfaces beyond forms

Discussion:

• How does it work within a form?
• How is it used to select widgets?
• Where else can node expressions be used for user-interfaces?

Links:

• SHACL 1.2 Core - Node Expressions