Implement URL redirects (server side ideally)

[andabak]

TODO create some redirects which will do the following

forward https://docs.astar.network/docs/learn/build2earn to https://docs.astar.network/docs/learn/dapp-staking/ forward https://docs.astar.network/docs/build/dappstaking to https://docs.astar.network/docs/learn/dapp-staking or https://docs.astar.network/docs/use/dapp-staking

One way is client redirecs, but Docusaurus docs suggest this should be only alternative to hosting redirects https://docusaurus.io/docs/api/plugins/@docusaurus/plugin-client-redirects