Update frontend build system to shed old dependencies, and address fallout from that (#521)

* get tests working and update copyright headers

* lint fix

* eslint ts update

* update CI to use NPM

* fix CI

* prettier

* npm, not yarn for docker

* remove unused package

* bump dockerfile to latest node LTS and no need for cache clean

* make frontend Dockerfile work and remove unused SUBSTRATE_TELEMETRY_SAMPLE

* remove final yarn references

* add another comment

* remove unused import

* remove more unused deps

* comment typo

README.md

@@ -40,7 +40,7 @@ To run the frontend make sure to grab the latest stable version of node and inst
 
 ```sh
 nvm install stable
-(cd frontend && yarn)
+(cd frontend && npm install)
 ```
 
 ### Terminal 1 & 2 - Backend
@@ -72,8 +72,8 @@ By default, `telemetry_core` will listen on 127.0.0.1:8000, and `telemetry_shard
 
 ```sh
 cd frontend
-yarn install
-yarn start
+npm install
+npm run start
 ```
 
 Once this is running, you'll be able to navigate to [http://localhost:3000](http://localhost:3000) to view the UI.