Add method for sanitizing URL.

A URL can only have a handful of characters in it without requiring any modifications (i.e., unencoded). These characters are `:`, `/`, `?`, `&`, and `=`, and they serve a specific purpose in the URL. All other characters need to be encoded in order to be included in the URL. Unencoded characters can result in unwanted behavior.

A method can be implemented inside the `BasePagedResponseGetter` class of the `src/comb_utils/lib/api_callers.py` module in order to sanitize the input URL so that all unencoded characters are encoded properly.

This issue was formed based on the changes made in #62.

Start in src/comb_utils/lib/api_callers.py and inspect the BasePagedResponseGetter class and how it receives or builds input URLs. Define the sanitization behavior there so URL characters outside the allowed unencoded set are encoded, then verify that the resulting URL preserves the intended delimiters and no longer contains unintended unencoded characters.

Written by the indexing model from the issue text.