Make frontend pure binary crate

[Septias]

On startup, cargo complains about colliding names of the binary and library crate from dc40-frontend.
As #6313 from cargo-crate gh says this is #6308 a check if multiple jobs produce the same files so dc40 gets compiled twice which increases load times.
By making dc40-frontend a pure binary crate this problem is solved.

The bin target `dc40-frontend` in package `dc40-frontend v0.1.0 (/home/septias/programming/dc40/frontend)` has the same output filename as the lib target `dc40-frontend` in package `dc40-frontend v0.1.0 (/home/septias/programming/dc40/frontend)`.
Colliding filename is: /home/septias/programming/dc40/frontend/target/wasm32-unknown-unknown/debug/deps/dc40_frontend.wasm
The targets should have unique names.
Consider changing their names to be unique or compiling them separately.
This may become a hard error in the future; see <https://github.com/rust-lang/cargo/issues/6313>.

[Simon-Laux]

please rebase this onto master and do a force push, there are like 16 unrelated commits in this pr

[Simon-Laux]

rebase needed

[Septias]

has some unneccessary changes. We can make a clean one if needed