Simplify the imports on the landing page

Docker script caused artifacts to still be built with OCaml 4.07.1.
Oops.

To keep up with Software Foundations, mainly.

Coq 8.12 has multi-char bullets (e.g. `--` or `***`).

Project Pane + nits

Fix CVE-2020-7660.

When building chunked packages using the CLI.

This precipitated some refactoing of package resolution code.
Also, while packages are loaded, a "wait" animation is shown in the
project toolbar.

(at last, yay ^^)

Brought over from v8.11+wacoq.

Package chunks

For building addons from jscoq/addons.

(Installs to OPAM.)

(Mostly brought about by elpi addon.)

To allow packages to be downloaded from node_modules, esp. mathcomp.

Remains in "wait" mode if no packages are specified in init_pkgs.

For Coq 8.12.0 release.

This seems needed for Coq 8.12