* add BalanceConversion trait and implementation * derive some useful traits on Imbalance * Update frame/support/src/traits/tokens/fungibles/imbalance.rs Co-authored-by: Xiliang Chen <xlchen1291@gmail.com> * make BalanceConversion error type configurable * add RuntimeDebug import and derive traits on other Imbalance * formatting * move BalanceConversion trait to frame-support * add necessary trait import Co-authored-by: Xiliang Chen <xlchen1291@gmail.com>