Make Teradata optional

[cgatian]

The snippets for these controls seem like they should be in another extension.

[thekalinga]

Material2 in its current state is not sufficient enough to build full blown Angular 2+ app. Many people who use Material2 would also need additional components.

Covalent is striving to keep upto date with material 2+ development & backed by Teradata. Seems reasonable enough for decent percentage of people to use both.

I think the split would make more sense when material 2 has matured enough to have atleast 80% of what material 1 has now.

I'll keep this ticket open just as a reminder to split.