Use ExportServices from climate-change-components

[ddohler]

Overview

Brief description of what this PR does, and why it is needed.

Demo

Notes

• As part of trying to diagnose some difficulties with compiling using a local version of climate-change-components, I discovered that the rxjs import migration here was incomplete. Because climate-change-components imports Observable the wrong way, it allows things to work that won't work once climate-change-components imports Observable correctly. I didn't end up merging the changes to climate-change-components that triggered these failures (precisely because they caused unexpected problems in other places and I didn't want to risk breaking unrelated functionality in Temperate and the Lab), but the additional imports here are (apparently) harmless and they prevent us from having to redo the work whenever Use recommended rxjs import form climate-change-components#49 gets resolved.
• I noticed as part of this that PNG download is apparently broken on Staging -- I think there was a regression in the current version of the PNG-saving library; the latest version seems to fix the problem.
• This is WiP until Add Export Services from Climate Change Lab climate-change-components#51 is merged and a new version is released. After that happens, this should be updated to pull in the latest version in package.json, and remove the dependencies for SVG export and file saving.

Testing Instructions

• Check out the code from Add Export Services from Climate Change Lab climate-change-components#51 in your development environment for that project.
• In the CC components repo, run yarn run build:library
• From this repo, run yarn install
• From this repo, run rsync -avrc --delete ../climate-change-components/lib-dist/ node_modules/climate-change-components/lib-dist/ <-- Substitute the path to your climate-change-components repo if that isn't correct.
• Fire up yarn run serve and confirm that you can still download PNGs of charts and that you get no compilation errors.
• Also confirm that you can still download JSON exports.

Checklist

• yarn run serve clean?
• yarn run build:prod clean?
• yarn run lint clean?

Connects azavea/temperate#1171

[ddohler]

This is no longer WiP and is ready for review; cc-components 0.4.0 has been released, and I've updated this to pull in the new dependency.