build/ci: add presubmit Jenkinsfile
This implements a basic presubmit Jenkinsfile which should be consumed
(in this CR already) by CI machinery running against review.monogon.dev.
This presubmit exercises the same build targets as the old, internal
Phabricator CI. The build executing agents are based off of the 'monogon
builder' Docker image defined within build/Dockerfile. A follow up CR
will remove the leftover of Phabricator CI machinery and explicitly
document how that agent image is built and used.
We also reformat a generated .bzl file to remove a spurious copyright
header. This appeases Gazelle/Fietsje checks.
Finally, we add a .gitignore which ignores build files to make the
Gazelle/Fietsje dirty checkout detection work correctly. The internal
version of the metropolis repository had an equivalent .gitignore which
wasn't carried over during the initial migration into the Monogon
monorepo.
Change-Id: Ib88b8b50dbc6fcd034757558697e6ae2334235b1
Reviewed-on: https://review.monogon.dev/c/monogon/+/26
Reviewed-by: Leopold Schabel <leo@nexantic.com>
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ac51a05
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+bazel-*