Add docs for monetaryCost

Please add documentation for monetaryCost in rst format, following the existing template.
https://gitlab.eclipse.org/eclipse-research-labs/hyper-ai-project/hypertool/-/blob/master/docs/functionality.rst?ref_type=heads

function_name

description

Kubernetes type: Annotation / Label / Taint

Dependencies:

• list of python packages

Parameters:

• list of params

Example Output:

• hyperai.eu/node-interface: eth0

Error Handling:

when ?

• the results when an exceptions is raised