Add RPC Builder to Substrate Node Template (#6808)

* Pulled RPC from node and populated the node-template's RPC builder with one example implementation

* surpress build errror

* dead_code

* Fixed module usage, removed copyright, removed rpc builder for light client + some comments

* added a comment for rpc extension

* Update bin/node-template/node/src/rpc.rs

Co-authored-by: Shawn Tabrizi <[email protected]>

* Update rpc.rs

* fix spacing

* more space to tabs

* more space to tabs

* Documenation nitpick

* Documentation nitpick

* Documentation nitpick

* Documentation nitpick

* Documentation nitpick

* pre-format

* Updated transaction payment API implemented for node template

* fix space and commented code

* fix long line

Co-authored-by: Shawn Tabrizi <[email protected]>
Co-authored-by: Dan Forbes <[email protected]>