Create UI for using Tags

[Rperry2174]

We are creating backend for tag support in #280. We also need a frontend that will allow users to drill down past just application name and look into specific tags for an application.

Over time we will likely expand the types of queries that can be made with tags and possibly even coming up with a (simple) Pyroscope specific query language that matches up with the way we store data in our storage engine. For that reason, we should have both a dropdown, but also an input field that will enable people to eventually type in specific queries (i.e. tag=hostname.*)

This component will likely go beneath the current "application name" dropdown and look something like this:

Over time we can make this component smarter where it can "autocomplete" based off the available options:

Here is a docker-compose to play with example linked above (Grafana + Loki):
https://github.com/jaegertracing/jaeger/tree/master/examples/grafana-integration

[petethepig]

@Rperry2174 Can you please send us a docker compose file so that we could play with this Loki + Grafana setup?

[Rperry2174]

closed in #296