Use modern JSX runtime with Babel, named exports, verbatim syntax

[colinrotherham]

This PR ensures dependencies like classnames and tslib are no longer bundled by Rollup and includes:

• New React JSX transform now enabled
• TypeScript verbatim module syntax with separate type imports
• Rollup uses Babel configured with Browserslist
• Default exports swapped with named exports
• Declaration maps allow debugging with real sources

Rollup also preserves (non-minified) CommonJS and ES modules with the correct file extensions too:

Following on from v6.0.0-beta.0 this PR also fixes these missing exports:

 describe('Index', () => {
   it('contains all expected elements', () => {
@@ -15,8 +15,10 @@
       'Breadcrumb',
       'Button',
       'Card',
+      'CardContext',
       'CharacterCount',
       'Checkboxes',
+      'CheckboxesContext',
       'ChevronRightCircleIcon',
       'Clearfix',
       'Col',
@@ -24,6 +26,7 @@
       'ContentsList',
       'CrossIcon',
       'DateInput',
+      'DateInputContext',
       'Details',
       'DoAndDontList',
       'ErrorMessage',
@@ -31,10 +34,15 @@
       'Fieldset',
       'Footer',
       'Form',
+      'FormContext',
       'FormGroup',
+      'FormGroupContext',
       'Header',
+      'HeaderContext',
+      'HeadingLevel',
       'Hero',
       'HintText',
+      'Icon',
       'Images',
       'InsetText',
       'Label',
@@ -43,6 +51,7 @@
       'NavAZ',
       'Pagination',
       'Radios',
+      'RadiosContext',
       'ReadingWidth',
       'ReviewDate',
       'Row',
@@ -51,6 +60,9 @@
       'SkipLink',
       'SummaryList',
       'Table',
+      'TableContext',
+      'TableSection',
+      'TableSectionContext',
       'Tabs',
       'Tag',
       'Textarea',

[colinrotherham]

Both PRs #272 and #273 have been merged in

[colinrotherham]

Thanks @ricksmith130 I've merged #270 into here too

[sonarqubecloud]

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.3% Duplication on New Code

See analysis details on SonarQube Cloud