feat(accordion): add accordion and accordion-group components

[liamdebeasi]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (npm run build) was run locally and any changes were pushed
• Lint (npm run lint) has passed locally and any fixes were made for failures

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Issue Number: resolves#17094

What is the new behavior?

• Add ion-accordion and ion-accordion-group components

Does this introduce a breaking change?

• Yes
• No

Other information

[liamdebeasi]

Accessibility Testing

"native" refers to this sample: https://www.w3.org/TR/wai-aria-practices/examples/accordion/accordion.html

Selecting Accordion

	native	Ionic
VoiceOver macOS - Chrome	Personal information, collapsed, button	Personal information, collapsed, button
VoiceOver macOS - Safari	Personal information, collapsed, button	Personal information, collapsed, button
VoiceOver iOS	Personal information, collapsed	Personal information, button, main, landmark, collapsed
Android TalkBack	Collapsed, personal information, button	Collapsed, personal information, button
Windows NVDA	Personal information, button, unavailable, collapsed	Clickable Personal Information button collapsed

Toggling Accordion

	native	Ionic
VoiceOver macOS - Chrome	Personal information, dimmed expanded, button	Personal information, expanded, button
VoiceOver macOS - Safari	Personal information, dimmed expanded, button	Personal information, expanded, button
VoiceOver iOS	Personal information, dimmed, expanded	Personal information, main, landmark, expanded
Android TalkBack	Expanded	Expanded
Windows NVDA	Unavailable, expanded	Expanded

AXE Issues

None!

TODO:

• NVDA prevents keyboard navigation from working with arrow keys