ci: add file with info about distros that we test

Useful to have easily accessible the info of all the distros that we
test, including the version of NM that they ship and their EOL dates so
we can know when to stop testing them.

For now this is only informative, but we can use this info, for example,
to generate the `.gitlab-ci/config.yml` file automatically for each
stable branch.

.gitlab-ci/distros-info.yml

@@ -0,0 +1,131 @@
+# Fedora:
+#   cadence: every 6 months
+#   support: 13 months
+# Image aliases: latest, rawhide
+fedora:
+- version: rawhide
+  support: yes
+  nm: main
+- version: 40
+  support: 2025-05-13
+  nm: 1.46
+- version: 39
+  support: 2024-11-12
+  nm: 1.44
+
+# CentOS Stream
+centos:
+- version: stream9
+  support: 2027-05-31
+  nm: main
+- version: stream8
+  support: 2024-05-31  ## EOL
+  nm: 1.40
+
+# RHEL:
+# Even minor versions:
+#   cadence: every year
+#   support: 2 years EUS + 2 years SAP / Enhaced EUS
+# Odd minor versions:
+#   cadence: every year (every other 6 months than even versions)
+#   support: 6 months
+rhel:
+- version: 9.5
+  support: yes
+  nm: main
+- version: 9.4
+  support: 2026-04-30
+  extended-support: 2028-04-30
+  nm: 1.46
+- version: 9.2
+  support: 2025-05-31
+  extended-support: 2027-05-31
+  nm: 1.42
+- version: 8.10  # last RHEL 8 release, maintenaince support only
+  support: 2029-05-31
+  extended-support: no
+  nm: 1.40
+- version: 8.8
+  support: 2025-05-31
+  extended-support: 2027-05-31
+  nm: 1.40
+# SAP / Enhaced EUS only:
+- version: 9.0
+  support: 2024-05-31
+  extended-support: 2026-05-31
+  nm: 1.36
+- version: 8.6
+  support: 2024-05-31
+  extended-support: 2026-05-31
+  nm: 1.36
+
+# Ubuntu:
+# LTS:
+#   cadence: every 2 years
+#   support: 5 years LTS + 5 years extended security
+# non-LTS (rolling):
+#   cadence: every 6 months
+#   support: 9 months
+# Image aliases: latest (LTS), rolling (LTS or non-LTS), devel
+ubuntu:
+- version: devel
+  support: yes
+  nm: main
+- version: 24.04
+  name: focal
+  support: 2029-05-31
+  extended-support: 2034-04-25
+  nm: 1.46
+- version: 22.04
+  name: jammy
+  support: 2027-06-01
+  extended-support: 2032-04-21
+  nm: 1.36
+- version: 20.04
+  name: noble
+  support: 2025-05-29
+  extended-support: 2030-04-23
+  nm: 1.22
+
+# Debian:
+#   cadence: every 2 years
+#   support: 3 years + 2 years LTS
+# Images aliases: stable, oldstable, oldoldstable
+debian:
+- version: devel
+  support: yes
+  nm: main
+- version: sid
+  support: yes
+  nm: main
+- version: 12
+  name: bookworm
+  support: 2026-06-11
+  extended-support: 2028-06-30
+  nm: 1.42
+- version: 11
+  name: bullseye
+  support: 2024-08-15
+  extended-support: 2026-08-31
+  nm: 1.30
+
+# Alpine:
+#   cadence: every 6 months
+#   support: 2 years
+# Image aliases: latest, edge (development)
+alpine:
+- version: edge
+  support: yes
+  nm: main
+- version: 3.20
+  support: 2026-04-01
+  nm: 1.46
+- version: 3.19
+  support: 2025-11-01
+  nm: 1.44
+- version: 3.18
+  support: 2025-05-09
+  nm: 1.42
+- version: 3.17
+  support: 2024-11-22
+  nm: 1.40