Deployment plan: save load v2

Thoughts

Major releases on editor + core should be synced
Therefore a "release" can include both core and editor features, sometimes which rely on each other (ie notify, json-utils, etc)

Tasks needed to support this standard release checklist:

[x] - Create v1 release checklist for core https://github.com/3DStreet/3dstreet/blob/main/CONTRIBUTING.md#release-checklist-for-this-repo
[x] - Create v1 release checklist for editor (also deployment instructions) https://github.com/3DStreet/3dstreet-editor/blob/master/README.md#release-checklist-for-editor-only
[x] - Where are release notes held - in each respective repo? Yes, via normal release mechanism. How are they found from the docs? Here: https://www.3dstreet.org/docs/development/releases
[x] - How has editor versioning been handled? (package.json) Does the 3dstreet editor have an npm package? None to date
[x] - Where to announce the release? Tw, Li, Yt, blog post? (Yes)
[x] - Where to store global release checklist? (3dstreet repo? docs?) stored here: http://3dstreet.org/docs/development/releases#release-checklist

Tasks needed before the 0.5 release:

[x] - bring core main up to date, do a release 0.4.2
[x] - bring editor up to date, do a release to match latest 0.4.x core https://github.com/3DStreet/3dstreet-editor/issues/350

Global release checklist:

[x] - Complete the release checklist for core
[x] - Complete release checklist for editor
[x] - Complete editor deploy
[x] - Smoke test on production 😬
[x] - Then share release notes on https://www.3dstreet.org/docs/development/releases
[x] - Share announcement on social media, email newsletter, etc

3DStreet / 3dstreet-editor