Show ens domain on address bar

[anxolin]

Description

Follow up to #869, show ENS domains on address bar

Proposal

1. When directly input in the url, load the address associated with an ENS domain and don't replace it with the address:
   https://.../address/vitalik.eth <- if it exists and it's valid
2. When searching for and end domain, use that as the url instead of the decoded address.

An additional/optional step would be, if searching by an address that has an ens domain pointing to it (similar to what Ramiro is doing for CowSwap), we could display the address in the UI OR replace the URL with given domain:
/address/0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 -> /address/vitalik.eth

Original issue gnosis/gp-ui#884 by @alfetopito