Estimated the required resources and possibility to rebase from the original polkadot-js

[uchu]

Currently, the Explorer is based on some non-official fork that had the required functionality at the time when the original one lacked it.

As there's now a huge difference between our version and the original and maybe it's almost impossible to rebase it and fix all the conflicts. However, I would suggest to at least make an estimation, so we can decided if it makes sense.

[uchu]

@TarasPotsikaylo @akorchyn Maybe you can also provide some more insights on that.