Consul UI: node metadata

#### Feature Description

We use node_meta/node-meta to register some key/value-pairs like description("frontend") or environment (dev, integration, qa, ...) that are valid for whole nodes. Quite similar to #4173 we would like to use this node specific metadata in the ui.

#### Use Case(s)

A search filter in the node view "show me all nodes with value X" is the preferred version. For our needs this does not have to be a full blown search engine like "A=foo && key B=bar". A full text search for "foo" is fine (to us), if it is easier to implement. This could be different in larger environments. Being able to see it at all (raw json or anything like that) e.g. in the node-specific view would be a nice start. This would make it way easier to get some first hints what this server is doing while using the node view and will be a great help, if you want to drill down to some data, when you know the metadata like "frontend".