Adding avatar resolution

### What feature should we add?

Implementing a function in the ens modules, called ```get_avatar``` which implements the ENIPS (https://docs.ens.domains/ensip/12/)
```Clients are expected to support a number of URI schemas, which aren't always web URIs, so the final result you see in your application will vary depending on how the library you are using has decided to handle avatar records.

http(s): - URI Scheme for HTTP(S) URLs. Libraries will most likely return the result directly.
ipfs: - URI scheme for IPFS hashes. Libraries may decide to fetch the result from a public gateway for you.
data: - URI Scheme for data URIs. Libraries will most likely return the result directly.
eip155: - The URI scheme for EIP-155 identifiers for linking to NFTs on Ethereum based chains. A little complicated to resolve manually, most libraries should resolve this for you and return the underlying resource.
```