Base: Add validator, account and transaction URLs

[kwunyeung]

Update the /validators/{operate_address} url to /validator/{operate_address}.

Update the /accounts/{address} url to /account/{address}.

Update the /transactions/{tx_hash} url to /transaction/{tx_hash}.

This make the urls more sensible as the pages are referring to a single entry. This also align with the legacy BD which other services, e.g. Keplr, is pointing to.

[ryuash]

This breaks restful practice and does not make sense as there are multiple validators and not a single entity.

Another example would be mintscan

Legacy BD is not following restful practices but BD 2.0 is.

This issue would not be an enhancement but a step backwards

[ryuash]

@yayay927 Instead of updating we will be adding these archived urls.

Goal:
Have both /validators/<validator_address> and /validator/<validator_address>

[yayay927]

@ryuash okay

[ryuash]

update: we might be able to redirect instead https://nextjs.org/docs/api-reference/next.config.js/redirects