Export demo datasource utils from shared; Add plop generator for shared entrypoint

[tinahollygb]

Export the demo datasource utils from shared

The previous PR #1477 created utils. These were not made available due to the exporting. This fixes that.

Plop generator for shared entrypoint

The current process for writing a new entry point has a lot of manual steps, many that can be missed during the development and review process. These changes add a generator yarn plop shared-entrypoint so we can generate all the required things.

You can test this by running it and using the example resources in the description:

 yarn plop
yarn run v1.22.19
$ plop
? [PLOP] Please choose a generator. shared-entrypoint - [shared] Generates a new entry point for the shared package
? A new entry point for the shared package, e.g. 'todos' to make import { createTodo } from 'shared/todos' todos
? Name of the first function to add to this file, e.g. 'createTodo' to make import { createTodo } from 'shared/todos' createTodo
✔  ++ /packages/shared/todos.d.ts
✔  ++ /packages/shared/src/todos/todos.ts
✔  ++ /packages/shared/todos.js
✔  ++ /packages/shared/src/todos/index.ts
✔  _+ /packages/shared/src/index.ts
✨  Done in 8.91s.

It creates a packages/shared/src/todos which has a file intended to put private/public functions, types, etc. todos.ts and a barrel file for exporting public functions:

tree packages/shared/src/todos
packages/shared/src/todos
├── index.ts
└── todos.ts

It creates the relevant files, which should now be able to be imported into the front-end and back-end packages without issue:

import { createTodo } from 'shared/todos';

[github-actions]

Your preview environment pr-1484-bttf has been deployed.

Preview environment endpoints are available at:

• https://growthbook-3100-pr-1484-bttf.growthbook.okteto.dev
• https://growthbook-3000-pr-1484-bttf.growthbook.okteto.dev