This diff introduces a websocket listener for 'BlockConnected' events, which then retrieves the latest alias registration fees from alias-server and checks whether prices have changed or not based on the length of the pricing array, before rendering as price preview in Alias.js.
At this point in time the chronik-client module is still being upgraded to work with the in-node chronik indexer, therefore it is not efficient to be making a blockheight comparison between server and cashtab arrays. This is needed due to the potential for multiple pricing tiers in the pricing array returned from alias-server, where the latest entry could have a startHeight into the future.
As a temporary mitigation it is assumed initial go live pricing will always be a single entry array. Once chronik-client has been upgraded, this price parsing logic will be updated to use the new websocket for blockheight comparisons. The intention is to reverse loop through `aliasPrices.prices` and parse for the latest array entry that has a startHeight within the chain's tipHeight.