Add support to search for Ordinals by text/namespace

[sabbyanandan]

From Ordiflow (https://ordiflow.com/)

One important feedback is, it would be great if you provide an API to search ordinals based on text/namespace (Eg: example.sats, 0.bitmap, example.x, example.unisat). Hiro API has the ability to fetch data based on inscription details but not based on the namespace. And hence I was forced to use unisat APIs for this scenario alone.