Create chain selection page

[Bullrich]

Base on a discussion between @mordamax and @mutantcornholio we should develop a "hub", or a landing page where all the available chains are shown, and the user picks the one he wants.

[itsbirdo]

The chain selection below could be moved in-line into the form.

The order can be:
Chain (Rococo, Westend, etc)
Network (Bridge Hub, Asset hub, etc)
Address

cc: @Bullrich

[mutantcornholio]

I think this idea is also alignes well with the whole "universal faucet" thing: supporting multiple currencies and chains in one instance of faucet, as well as being able to have multiple instances of faucet backend in one deployment.
Will create an epic for it soon.

[mordamax]

I'd probably think of it as parity supported test chains, since we manage seeds/balances.
While the other testnet owners, which are not managed by our team, could just fork this repo and deploy it on their own environment, providing necessary testnets configs and looking after its secrets/balances.

or may be i don't fully understand how exactly other testnets will be added, and who will control the balances etc

[itsbirdo]

As an alternative, the faucet could still list other networks and then just redirect the page if the user selects that Chain.

e.g. In the Chain dropdown, Frequency is an option
Upon selecting Frequency, the page redirects to faucet.rococo.frequency.xyz

At least it surfaces the other faucets and makes them discoverable