Add new tesnet paseo

[bee344]

Rel: #351
With the changes in the tesnets mentioned in the related issue, we should update the code to also include paseo. There will be a time where both rococo and paseo will coexist but eventually only paseo will remain, so then we should remove rococo from the code.

[IkerAlus]

We have concrete plan and dates to deprecate Rococo: https://forum.polkadot.network/t/rococo-to-be-deprecated-in-october/8702