Balance conversion for balance types

[Tbaut]

closes #375

This adds the token at the end of the field for manual extrinsics in case the field is expecting a balance. It will then convert the value in plank with the right amount of 0s.

To test:

• Craft a manual extrinsic that needs a value, for instance balances.transfer or bounties.proposeBounty
• check that the token is visible
• check that when the tx is done, the right amount in plank is submitted. Note that for balances.transfer, the overview converts it back to human readable values, like in my screenshot

Submitting

Verifying

[Lykhoyda]

If it's possible please refactor the method transformParams. Both scenarios mentioned in the description work fine 👍

[Tbaut]

The refactor is in, very inspired by your code, thank you very much. I chose to only extract to functions some logic when

• it was more than 1 line
• it was re-used
• it did not require to duplicate code

This means that things like for instance the Balance handling is still on several lines, because I didn't want to duplicate the bnResult = inputToBn(chainInfo.tokenDecimals, converted);, but it should be much easier to read now still, on top of the simplification of not using a convert batching the map etc..

[Lykhoyda]

can we maybe move it to the log method and comment it?

[Tbaut]

After offline discussion we're keeping this around for a bit.