bosco start - be smarter

[cliftonc]

There are a lot of reports of bosco being slow, which of course means that it starting the services and / or compiling the JS for cdn is slow.

We should be smarter about a number of things:

1. If you run bosco start in the team folder, without a -r filter, warn the user this isn't a smart thing to do, and they are probably better off running it in the specific service they want to work on.
2. Update the engineering guide to explain best practice - e.g. bosco morning on your team folder, but then always go into the service you want to work on and bosco start -d, new tab, bosco cdn, new tab, npm run dev (or however you start the service in dev mode: https://github.com/tes/app-resource-sales-tool/blob/master/package.json#L12).
3. Ensure that for all projects that have their own build and minification step, that we tell Bosco not to re-minify it. e.g. https://github.com/tes/app-resource-sales-tool/blob/master/bosco-service.json#L21
4. Move services to Node6 + es2017 babel preset to speed up startup (where currently using full babel or node4): https://github.com/tes/app-resource-sales-tool/blob/master/.babelrc#L2

.... ?