* [Cards] New API Header files (#2886)
* header files
* rename to MDCCardCollectionCell
* update for review
* update to review
* update to review
* [Cards] Full Implementation (#2892)
* cards core implementation
* updates to API and fixes from doc
* small fixes
* podspec, examples, and tests
* small fixes
* small fix
* small fix
* update inkView API and some small nits
* refactor API and code
* refactor API and code
* remove private header
* rename to MDCCardCollectionCell
* updates to api review
* update based on reviews
* fix tests
* [Cards] Initial Docs
* updates to encoding
* small fix
* pr update
* pr update
* pr update
* pr update
* pr update
* pr update
* pr update
* ink api update
* ink api update
