Add array size validation to the openapi-generator C templates

[davidjwbbc]

Description

Modify the mustache templates in open5gs-tools/openapi-generator-templates/c/ to add the following validation:

1. Add validation to confirm that objects parsed from JSON that include arrays with minItems and/or maxItems set contain a valid number of items after parsing of the array is complete.
2. Add validation when converting a modelled object to JSON to confirm that arrays contain at least minItems number of items if minItems is given for the array and no more than maxItems if maxItems is given for the array in the OpenAPI description. Conversion to JSON fails if an array does not contain a valid number of items.