feat(v2): initial v2 implementation

add multi-arch (arm & x64) image
add multiple pipelines (ci now creates the "default" pipeline as a shorthand)
simplify devenv flake input
merge all cache options together, now $NIX_CI_CACHE_STRATEGY decides how the cache works
setup_nix_ci and finalize_nix_ci are now flake packages and work standalone
the specific image is not needed anymore, any image with the right dependencies works
runner cache is not the default anymore (because it sucked most of the time)
the pipeline is selected by $NIX_CI_PIPELINE_NAME or if empty by $CI_PIPELINE_SOURCE,
so for the old behaviour $NIX_CI_PIPELINE_NAME=default is needed, future
work will be needed to handle this more nicely

README.md

@@ -21,6 +21,7 @@ Also makes it possible to split CI parts in a separate module which can be impor
     ...
     
     perSystem = {pkgs, ...}: {
+      # ci is a shortcut and creates a "default" pipeline
       ci = {
         stages = ["test"];
         jobs = {
@@ -33,6 +34,11 @@ Also makes it possible to split CI parts in a separate module which can be impor
           };
         };
       };
+      # runs on a merge request for example
+      pipelines."merge_request_event" = {
+        stages = ["some_stage"];
+        jobs = { ... };
+      };
       ...
     }
   }
@@ -43,9 +49,6 @@ Also makes it possible to split CI parts in a separate module which can be impor
 # .gitlab-ci.yml
 include:
   - component: gitlab.com/TECHNOFAB/nix-gitlab-ci/nix-gitlab-ci@<version>  # recommendation: use the latest version (try not to use latest)
-    inputs:
-      # specify inputs here, for example:
-      image_tag: latest-cachix
 ```
 
 ## Utilities
@@ -63,16 +66,15 @@ The `build:nix-ci` job has a different special environment variable `NIX_CI_FORC
 You can run any job's script (+ before and after) locally with Nix for easier testing:
 
 ```sh
-nix run .#gitlab-ci-job:<name>
+#                                /  pipeline name, like "default"
+nix run .#gitlab-ci:pipeline:<pipeline name>:job:<name>
 ```
 
-There is also `.#gitlab-ci-job-deps:<name>` which generates and exports the required environment variables for each job:
+There is also `.#gitlab-ci:pipeline:<pipeline name>:job-deps:<name>` which generates and exports the required environment variables for each job:
 
 - PATH (with all deps)
 - any custom env variables which contain store paths to not break stuff when switching archs
 
-Please see #8 for some issues and further improvements on this.
-
 ## Thanks to
 
 Some parts of this implementation are adapted/inspired from https://gitlab.com/Cynerd/gitlab-ci-nix