closes#2498
solves part of #3365
Note: difficult to test the event emit in SwitchToFastSync part, might need to change `stateSyncReactor` to an interface in the `nodeImpl` struct
* docs theme
* vuepress-theme-cosmos
* version bump
* changes to docs
* more code changes
* sidebar order fix
* moar changes
* fixed dev sessions title
* fixed dev sessions title, again
* specs should show up in sidebar
* contents cards
* version bump
* sidebar, rpc
* version bump
* custom footer and super naive search
* version
* minor change to vuepress
* move swagger file
* pre and post scripts
* build
* changed docs build process
* added deployment config
* updated versions file and added deployment filters