Modernize forms library

[pjm17971]

Umbrella issue for work on forms library:

• [ ] Move library to Typescript
• [ ] Remove flexbox-react code
• [x] Update to react-bootstrap (fix icons)
• [ ] Add storybook for development, testing and docs
• [ ] Update to latest version of react-select, combine with react-window
• [ ] Overhaul build setup (rollup)

Components that need to work:

• [x] TextEdit
• [ ] TextArea
• [ ] DateEdit
• [ ] Chooser (based on react-select)
• [ ] AsyncChooser (based on react-select)
• [ ] TagsEdit (based on react-select)

Additional components

• [ ] List and list HOC
• [ ] Views

Covered examples:

• [ ] Basic form with tri-state edit modes (always, selected and never)
• [ ] Dynamic changing form
• [ ] List contact example

Storybook:

• [x] Initial setup so we can add stories in Typescript
• [ ] Snapshot testing
• [ ] Docs