Convert to monorepo and revamp build system

[Methuselah96]

Main code changes

• Converts to monorepo, mainly so demos can use the master version of jsondiffpatch instead of using a URL. New directory structure is:
  • packages/jsondiffpatch
  • demos/console-demo
  • demos/html-demo
  • demos/numeric-plugin-demo
• Revamp build system
  • Remove bundling with Rollup in favor of just transpiling the modules using TypeScript
  • Switch to ESM-only. The ecosystem has enough ESM-only packages, that consumers should know how to deal with it at this point.
  • Add "exports" field to "package.json"
• Use esbuild to bundle code for html-demo
• Remove formatter exports from main entry-point. This allows using jsondiffpatch without depending on DOM types from the HTML formatter, and excludes importing chalk by default (fixes compile errors when not including dom types #323).

Breaking changes for consumers

• ESM-only
• No default export. Import using import * as jsondiffpatch from 'jsondiffpatch or import individual methods.
• Formatters must be imported from subpaths:
  • import * as annotatedFormatter from 'jsondiffpatch/formatters/annotated';
  • import * as baseFormatter from 'jsondiffpatch/formatters/base';
  • import * as consoleFormatter from 'jsondiffpatch/formatters/console';
  • import * as htmlFormatter from 'jsondiffpatch/formatters/html';
  • import * as jsonpatchFormatter from 'jsondiffpatch/formatters/jsonpatch';
• Updated CSS imports:
  • import 'jsondiffpatch/formatters/styles/html.css';
  • import 'jsondiffpatch/formatters/styles/annotated.css';
• Supported Node versions: ^18.0.0 || >=20.0.0

Remaining work before next release

• Disable text diffing by default to reduce bundle size