feat(tabs): implement manual and auto activation modes for keyboard navigation - master

[georgianastasov]

Closes #14839

Additional information (check all that apply):

• Bug fix
• New functionality
• Documentation
• Demos
• CI/CD

Checklist:

• All relevant tags have been applied to this PR
• This PR includes unit tests covering all the new code (test guidelines)
• This PR includes API docs for newly added methods/properties (api docs guidelines)
• This PR includes feature/README.MD updates for the feature docs
• This PR includes general feature table updates in the root README.MD
• This PR includes CHANGELOG.MD updates for newly added functionality
• This PR contains breaking changes
• This PR includes ng update migrations for the breaking changes (migrations guidelines)
• This PR includes behavioral changes and the feature specification has been updated with them

[ChronosSF]

@georgianastasov , @kacheshmarova , can anyone from your team validate this? We are trying to close 18.2 and if this doesn't get in master in a few days tops it's going to be left for 19.x

[RivaIvanova]

The Space key default behavior should be prevented in both activation modes.
If the mdoe is auto and I press Space on an active tab, the page is scrolled. This is not reproducible in WC.