Add force remove vesting (#1982)
This PR exposes a `force_remove_vesting` through a ROOT call. See linked [issue](https://github.com/paritytech/polkadot-sdk/issues/269) --------- Co-authored-by: georgepisaltu <[email protected]> Co-authored-by: command-bot <> Co-authored-by: Dónal Murray <[email protected]>