Fix links to /nix/store libraries in linux binaries

DFX

fix: ic-ref linux binary no longer references /nix/store

This means dfx start --emulator has a chance of working if nix is not installed.
This has always been broken, even before dfx 0.7.0.

fix: replica and ic-starter linux binaries no longer reference /nix/store

This means dfx start will work again on linux. This bug was introduced in dfx 0.8.2.

feat: replaced --no_artificial_delay option with a sensible default.

The --no-artificial-delay option not being the default has been causing a lot of confusion.
Now that we have measured in production and already applied a default of 600ms to most subnets deployed out there,
we have set the same default for dfx and removed the option.

Motoko

Updated Motoko from 0.6.10 to 0.6.11.

• Assertion error messages are now reproducible (#2821)