Add initial github CODEOWNERS file

Limits a bit who has to approve changes to what files. This is far from
complete, but rather testing out the system. Some of the more important
files have been added for the sake of evaluating this in this
repository.

.github/CODEOWNERS

@@ -0,0 +1,26 @@
+# Defining who has to review changes to what files.
+# Try to keep the entries sorted alphabetically, so they end up in the same order as
+# they would if you listed the entire repository as a tree.
+
+# Container images used for building the app are owned by respective team leads and tech lead
+/building/android-container-image.txt @faern @albin-mullvad
+/building/linux-container-image.txt @faern @raksooo
+
+# Developer signing keys must be approved by team/tech leads
+/ci/keys/ @faern @raksooo @pinkisemils @albin-mullvad
+
+# Desktop build server files owned by desktop leads
+/ci/buildserver* @faern @raksooo
+/ci/linux-repository-builder/ @faern @raksooo
+
+# Cargo deny config must be approved by tech lead or desktop team lead
+**/deny.toml @faern @raksooo
+
+# Changes to what CVEs are ignored must be approved by leads
+**/osv-scanner.toml @faern @raksooo @pinkisemils @albin-mullvad
+/.github/workflows/osv-scanner*.yml @faern @raksooo @pinkisemils @albin-mullvad
+
+# The CODEOWNERS itself must be protected from unauthorized changes,
+# otherwise the protection becomes quite moot.
+# Keep this entry last, so it is sure to override any existing previous wildcard match
+/.github/CODEOWNERS @faern @raksooo @pinkisemils @albin-mullvad