fix: update gas parameters for a parachain, units, and miscellaneous …

…fixes and cleanups (#6)

* fix: 18 decimals, add .await, update UncheckedExtrinsic

* fix: gas set properly

* chore: cleanup unused code

* chore: remove stray comment

* fix: small fixes after rebase

* style: cargo fmt

* chore: update naming from frontier to parachain-template

* chore: update comment