Refactor/project structure (#3085)

* refactor project structure

* environment-based default registry

* fix tests

* update build container

* use docker platform for iso build emulation

* simplify compat

* Fix docker platform spec in run-compat.sh

* handle riscv compat

* fix bug with dep error exists attr

* undo removal of sorting

* use qemu for iso stage

---------

Co-authored-by: Mariusz Kogen <k0gen@pm.me>
Co-authored-by: Matt Hill <mattnine@protonmail.com>

core/src/bins/deprecated.rs

@@ -0,0 +1,9 @@
+pub fn renamed(old: &str, new: &str) -> ! {
+    eprintln!("{old} has been renamed to {new}");
+    std::process::exit(1)
+}
+
+pub fn removed(name: &str) -> ! {
+    eprintln!("{name} has been removed");
+    std::process::exit(1)
+}