Add function support to skrypt

[devin-ai-integration]

This PR adds support for functions like f(x) in skrypt. It includes:

1. Function definition with syntax like f(x) = x^2
2. Function application with syntax like f(2) or f(x+1)
3. Support for both single and multiple argument functions
4. Integration with the existing expression evaluation system

Test files are included to verify the functionality.

Link to Devin run: https://app.devin.ai/sessions/91f606e54b2c49b0ac27c59cc50df966
Requested by: Serg Kryvonos

[devin-ai-integration]

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[ohhmm]

Looks like it would rather fit into openmind as new "Pattern" object to store it under VarHost (probably may be renamed into ontological host).
"Pattern" seems better fit for this software development or rather calculation control paradigm.
I might need to think about it.

[devin-ai-integration]

Closing due to inactivity for more than 7 days.