Move sc-client into sc-service (#5502)

* Drop client from sc-network and sc-client-db, move LongestChain to sc-client-api

* move leaves, cht, in_mem to sc-client-api, drop client from sc-finality-grandpa

* drop sc-service from sc-rpc

* drop sc-service from sc-consensus-aura

* drop sc-client from manual-seal and babe

* drop sc-client from utils/frame/rpc/system and utils/frame/benchmarking-cli

* drop sc-client from bin/node and bin/node-template

* drop sc-client

* fix tests

* remove check -p sc-client from gitlab.yml

* fix warnings

* fixes ui test

* fix light client tests

* adds associated Client type to AbstractService

* adds UsageProvider to Client

* fixed ui test, again

* tried and failed to get node-cli to compile for wasm

* thanks to tomaka for helping me get node-cli to compile for wasmm

* ui test pls pas 



* all tests passing 🪄

* no_run documentation code

* rm -f documentation code

* ClientProvider

* fix mega trait

* move LongestChain to sc-consensus, use adds minimal bounds to AbstractService::Client

* adds license to sc-consensus

Co-authored-by: Benjamin Kampmann <ben@parity.io>