entrpoint now uses exec to call the entrypoint command thus not spawing a subshell
updated uci shell code and added /root/shell so to avoid constant warning about it missing.
add /opt/bin to path in dockerfile
refactored: Dockefile template
refactor: example and move src/ there a simple example
new: distros.csv holds table of valid distros, their images and install/update commands
refactor: various fixes and adjustment in response to above
refactor: help vastly improved and updated
refactor src/ to be just a basic build
add examples
write up help.md and usage subcommand
add test folder for dev testing
improve install script
many numerous improved to build script,
moved portions of build script to functions in helpers.lib
support try using build environment file
refactor Dockerfile to use heredoc and RUN --mount instead of COPY
refactor Dockerfile init RUN to copy /bin and env directories from source always
user build.env and run.env for additional build and run environment
bake run.env into image