Unfortunately 13cfa87a82 broke the Svelte
language tools - presumably having paths outside of the repo is confusing
them.
As a plan B, the symlinks have been shifted to a single subdir. Along
with some exclusions in the VS Code config, this should allow VS Code
to continue to work out of the box, but the docs will need updating
to reflect the extra work required for PyCharm/IntelliJ.
+ fix svelte-check execution on a system without node installed. It
still throws up some errors that are presumably caused by our multiple
rootDirs - not sure if there's an easy way to work around that.
Recommend removing ts/node_modules folder before attempting to
build after this update.
This moves ts/node_modules into the root of the project to work around
https://github.com/ankitects/anki/pull/1405#issuecomment-936213861
Also fixes the sass errors shown when running scripts/svelte-check
