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>

build/os-compat/buildenv.Dockerfile

@@ -1,4 +1,4 @@
-FROM debian:forky
+FROM debian:trixie
 
 RUN apt-get update && \
     apt-get install -y \
@@ -12,35 +12,14 @@ RUN apt-get update && \
     jq \
     gzip \
     brotli \
-    qemu-user-static \
-    binfmt-support \
     squashfs-tools \
     git \
-    debspawn \
     rsync \
     b3sum \
-    fuse-overlayfs \
     sudo \
-    systemd \
-    systemd-container \
-    systemd-sysv \
-    dbus \
-    dbus-user-session \
     nodejs
 
-RUN systemctl mask \
-    systemd-firstboot.service \
-    systemd-udevd.service \
-    getty@tty1.service \
-    console-getty.service
-
 RUN git config --global --add safe.directory /root/start-os
 
-RUN mkdir -p /etc/debspawn && \
-    echo "AllowUnsafePermissions=true" > /etc/debspawn/global.toml
-
 RUN mkdir -p /root/start-os
 WORKDIR /root/start-os
-
-COPY docker-entrypoint.sh /docker-entrypoint.sh
-ENTRYPOINT [ "/docker-entrypoint.sh" ]