feat(md-fab-speed-dial): implementation

[jefersonestevo]

Fixes #860

[jelbourn]

Hi @jefersonestevo

As outlined in our contributing guide, the first step in working on a large feature like this is to open an issue for discussion. Going from there, we always start with a design document and design review with the team. We go through these steps to ensure that everything in the library meets our standards for accessibility, i18n, and consistency with the rest of the code-base.

Feel free to open a new issue (or start a discussion on the existing one) to start discussion on your proposed feature.

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}