Use Polkadot Constants instead of Hardcoding (#868)

* added Polkadot constants

* remove hardcoded constants

* cargo +nightly fmt

* add const existential deposit

* update

* cargo +nightly fmt

* not pulling

* readd constants.rs modules

* update

* Cargo.lock

* update

* add balance constants

* Update polkadot-parachains/statemine/src/constants.rs

Co-authored-by: Alexander Popiak <alexander.popiak@gmail.com>

* cargo fmt

Co-authored-by: Alexander Popiak <alexander.popiak@gmail.com>