Fix dev tokens not showing in dev and deploy previews

[dib542]

Dev tokens (local tokens named tokenA, tokenB, tokenC, etc ...) don't show correctly in the user's bank balances and in the token picker.

Once that issue was fixed it was found and resolved that it should be possible to pay the chain fees using a dev token as the fee token. This was achieved by overwriting the token base attribute with the dev token denom, as the base attribute (which is named coinMinimalDenom in the Keplr ChainInfo object type, is what determines the fee token to be used with the Keplr wallet.