Define that for a search request, components are the search components

[Relequestual]

#11 asks if we need to specify the versions of components in the search component.
My intention was to never have a "search component", and in stead allow components at the root level of a search request to represent the components to be used by a search, and then to have metadata components in the metadata object (meta.components).

If I can get a few nods that this makes sense, I'll make a PR.
Otherwise, we need further discussion.

(Blocks #11 )

[fschiettecatte]

This is fine with me.

[Relequestual]

It looks like after this discussion, I've defined that search components be nested under query.components. I think this was to align better with other proposals. (see model 2 in ga4gh-discovery/data-connect#32 (comment))
As such I'll close this, and #11.

@fschiettecatte Please re-open if you fee this is not OK.