As opposed to just the library

E.g. forbid items with incorrect type to be inserted in the database

This will change back when we have any decent
authentication mechanism

Now that we have content on the main site, better point there.

Because official rustup does this by default.

Otherwise, rust/cargo versions are just too old
to compile the dependencies of the project
(smallvec, rusqlite, etc).

Also, this is the officially recommended way
to install Rust in the community.