Added search by tag name

[rmgpinto]

Added two changes:

1. Search for tags (layout similar to search for columns);
2. Tags are now clickable and navigate directly to a search of that tag name.

[rmgpinto]

jaffle_shop needs to have tags to test this PR.
Added PR #16 to jaffle-shop.

[drewbanin]

hey @rmgpinto - thanks for making that jaffle-shop update! You'll need to re-compile the jaffle-shop project and copy the resulting .json files into the data/ dir. We could automate this in the CI process, bit it's currently manual.

Let me know if you'd like a hand with that - happy to help!

[rmgpinto]

If you wouldn't mind. I'm getting an error running dbt seed on jaffle_shop:

Runtime Error in seed raw_orders (data/raw_orders.csv)
  Cannot escape <class 'datetime.date'>

[drewbanin]

I just merged this PR: #33

You should be able to pull in master to see tags in the CI build!

[rmgpinto]

Thanks @drewbanin.
The CI build seems very nice, searching for st displays search on model name, columns and tags simultaneously.

[drewbanin]

This is wonderful! Thanks for making this PR @rmgpinto -- Approved, and slated for release in 0.14.0 (tracked in dbt/#1474)