nva-settings

Added utilities for checking and configuring the API client with the correct headers based on config.

This commit adds several utility functions to check whether a given value is an array of a specific type, and to configure the API client with the correct headers based on configuration settings. These utilities are used in the ProjectsByUserBlock plugin to retrieve the API client instance and configure it accordingly. The added functionality includes checking whether a certain key is present in an array, and configuring the API client instance with the hostname and client ID/secret if applicable.