add eras-client for projects stats callouts

[yuenmichelle1]

Adding simple ERAS client for Project Stats Callouts.

I mainly focused on callouts that will be used for project stats (as opposed to using statsClient on PFE).

One thing I did not add for eras client are the future callouts that will be used. Eg. Getting classification counts by user_group (/classifications/user_groups/:id or getting classification count by user /classifications/users/:id). I figured that would be done in a future iteration when we are ready to cross that bridge. (I don't mind adding it on now if we want to have it available in PJC now).

[eatyourgreens]

We have a new API client in the monorepo. Should the Eras client be added to that, so that @mcbouslog can use it in the work that he is doing?

[eatyourgreens]

I think you would just need to copy this file and add erasHost to the config.

https://github.com/zooniverse/front-end-monorepo/blob/master/packages/lib-panoptes-js/src/talkAPI.js

[yuenmichelle1]

We have a new API client in the monorepo. Should the Eras client be added to that, so that @mcbouslog can use it in the work that he is doing?

Ah. @eatyourgreens fair point. My main goal of updating PJC is to replace PFE project stats (replacing anything that currently uses the slow running Elasticsearch stats service, and eventually shutting down ES stats service) with ERAS stats callouts.

My plan is to do a minimal lift to do the replacement and then when @mcbouslog is ready he can do update API client in monorepo with any other changes he may need.

[mcbouslog]

Code changes LGTM 👍 . Incrementally adding functionality (if needed here, as opposed to an eras client in FEM/panoptes-js) sounds good.

I ran PFE locally and npm linked these changes and confirmed classifications and comments eras requests functioned as expected ✅ .

I'll merge this PR then create a (minor) release unless there's a preference or suggestion otherwise.

[eatyourgreens]

Sounds good to me. You can probably get rid of panoptes-client/lib/stats-client too, as a breaking change.

Something I learnt yesterday: Next.js data-fetching uses fetch in Node and in the browser. So the user-groups work in the monorepo should use fetch, not superagent, to get stats data.

[yuenmichelle1]

Code changes LGTM 👍 . Incrementally adding functionality (if needed here, as opposed to an eras client in FEM/panoptes-js) sounds good.

I ran PFE locally and npm linked these changes and confirmed classifications and comments eras requests functioned as expected ✅ .

I'll merge this PR then create a (minor) release unless there's a preference or suggestion otherwise.

@mcbouslog thanks for closing the loop on the changes. You're amazing! 🎉
@eatyourgreens @mcbouslog thanks for review :)