Improve asset sizes for core & plugins

There are a couple of low-hanging fruits to reduce asset sizes for core & plugins:

- [x] Fix code-splitting (seems to got broken between `3.1` and `3.2`) [#7598]
- [x] Remove obsolete dependencies (also from vendor bundle if referenced): [#7564]
- [x] `c3` (+ loading of stylesheet in `App`)
- [x] `d3`
- [x] `dc` (+ loading of stylesheet in `App`)
- [ ] Remove double inclusion of `moment` in vendor bundle (through `moment-timezone`)
- [ ] Remove loading of `jQuery.dynatable` stylesheet [#7601]
- [ ] Enable tree shaking for webpack
- [x] Remove the need for `{ module: 'cjs' }` in babel config [#7598]
- [ ] Replace imports of default export of `lodash` with partial imports
- [x] Load `react-ace-builds` asynchronously, also from plugins [already done, no PR necessary]