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 <shawntabrizi@gmail.com>

* 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 <shawntabrizi@gmail.com>
Co-authored-by: Dan Forbes <dan@danforbes.dev>

substrate/Cargo.lock

@@ -3789,7 +3789,9 @@ dependencies = [
 name = "node-template"
 version = "2.0.0-rc5"
 dependencies = [
+ "jsonrpc-core",
  "node-template-runtime",
+ "pallet-transaction-payment-rpc",
  "sc-basic-authorship",
  "sc-cli",
  "sc-client-api",
@@ -3797,8 +3799,13 @@ dependencies = [
  "sc-consensus-aura",
  "sc-executor",
  "sc-finality-grandpa",
+ "sc-rpc",
+ "sc-rpc-api",
  "sc-service",
  "sc-transaction-pool",
+ "sp-api",
+ "sp-block-builder",
+ "sp-blockchain",
  "sp-consensus",
  "sp-consensus-aura",
  "sp-core",
@@ -3808,6 +3815,7 @@ dependencies = [
  "sp-transaction-pool",
  "structopt",
  "substrate-build-script-utils",
+ "substrate-frame-rpc-system",
 ]
 
 [[package]]
@@ -3817,6 +3825,7 @@ dependencies = [
  "frame-executive",
  "frame-support",
  "frame-system",
+ "frame-system-rpc-runtime-api",
  "pallet-aura",
  "pallet-balances",
  "pallet-grandpa",
@@ -3825,6 +3834,7 @@ dependencies = [
  "pallet-template",
  "pallet-timestamp",
  "pallet-transaction-payment",
+ "pallet-transaction-payment-rpc-runtime-api",
  "parity-scale-codec",
  "serde",
  "sp-api",