Notemine should be monorepo

[dskvr]

- notemine-rust (cargo package `notemine`): miner binary
- notemine-js (npm package `notemine`): `notemine-rust` wasm build for web.
    - notemine - basic js bindings
    - notemine/observables - wrapped in observables
    - notemine/svelte - `notemine/observables wrapped for svelte
    - notemine/react - `notemine/observables wrapped for react
    - notemine/vue - notemine/observables wrapped for vue
- notemine-demos
  - vanilla-js
  - svelte
  - react
  - vue
  - rust