Make Goerli work again

[manuelwedler]

This PR makes the new wizard usable on goerli testnet. It adds an selector on the first page to let the user choose to use Mainnet or Goerli.

[fredo]

Here is the code which we could get rid of with your pending transaction nonce change

raiden-wizard/raiden_installer/transactions.py

Line 67 in a0b60f7

def approve(w3, account, allowed_address, allowance: Wei, token: Erc20Token):

[manuelwedler]

I'll add a commit for this change!

[fredo]

How complex would it be to change the Service Token Ticker to "SVT" when being on goerli? It is currently called RDN. To be copmpliant with the naming of the actual contract it would be nicer to have it called SVT (and to not be confused).

I see changes necessary in tokens.py and raiden-wizard/resources/conf/goerli.toml

[manuelwedler]

Yes you are right, that would be much nicer. I think it could be easy. I will try it.

[fredo]

Thanks a lot!

[fredo]

LGTM now! thanks for the changes