[nrf noup] ci: add downstream-only NCS customizations

Add Jenkinsfile, .gitlint, and backport workflow files.

Signed-off-by: Thomas Stilwell <Thomas.Stilwell@nordicsemi.no>
Signed-off-by: Ulrich Myhre <ulrich.solli.myhre@nordicsemi.no>
Signed-off-by: Chris Bittner <chris.bittner@nordicsemi.no>
Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
Signed-off-by: Johann Fischer <johann.fischer@nordicsemi.no>
(cherry picked from commit 624bd7c)

Author: thst-nordic

.github/workflows/backport.yml

@@ -0,0 +1,19 @@
+name: Backport
+on:
+  pull_request:
+    types:
+      - closed
+      - labeled
+
+jobs:
+  backport:
+    runs-on: ubuntu-18.04
+    name: Backport
+    steps:
+      - name: Backport Bot
+        uses: Gaurav0/backport@v1.0.24
+        with:
+          bot_username: NordicBuilder
+          bot_token: 151a9b45052f9ee8be5a59963d31ad7b92c3ecb5
+          bot_token_key: 67bb1f1f998d546859786a4088917c65415c0ebd
+          github_token: ${{ secrets.GITHUB_TOKEN }}

.gitlint

@@ -0,0 +1,57 @@
+# All these sections are optional, edit this file as you like.
+[general]
+ignore=title-trailing-punctuation, T3, title-max-length, T1, body-hard-tab, B3, B1
+# verbosity should be a value between 1 and 3, the commandline -v flags take precedence over this
+verbosity = 3
+# By default gitlint will ignore merge commits. Set to 'false' to disable.
+ignore-merge-commits=true
+# Enable debug mode (prints more output). Disabled by default
+debug = false
+
+# Set the extra-path where gitlint will search for user defined rules
+# See http://jorisroovers.github.io/gitlint/user_defined_rules for details
+extra-path=../../zephyr/scripts/gitlint
+
+[title-max-length-no-revert]
+line-length=72
+
+[body-min-line-count]
+min-line-count=1
+
+[body-max-line-count]
+max-line-count=200
+
+[title-starts-with-subsystem]
+regex = ^(?!subsys:)(([^:]+):)(\s([^:]+):)*\s(.+)$
+
+[title-must-not-contain-word]
+# Comma-separated list of words that should not occur in the title. Matching is case
+# insensitive. It's fine if the keyword occurs as part of a larger word (so "WIPING"
+# will not cause a violation, but "WIP: my title" will.
+words=wip
+
+[title-match-regex]
+# python like regex (https://docs.python.org/2/library/re.html) that the
+# commit-msg title must be matched to.
+# Note that the regex can contradict with other rules if not used correctly
+# (e.g. title-must-not-contain-word).
+#regex=^US[0-9]*
+
+[max-line-length-with-exceptions]
+# B1 = body-max-line-length
+line-length=72
+
+[body-min-length]
+min-length=3
+
+[body-is-missing]
+# Whether to ignore this rule on merge commits (which typically only have a title)
+# default = True
+ignore-merge-commits=false
+
+[body-changed-file-mention]
+# List of files that need to be explicitly mentioned in the body when they are changed
+# This is useful for when developers often erroneously edit certain files or git submodules.
+# By specifying this rule, developers can only change the file when they explicitly reference
+# it in the commit message.
+#files=gitlint/rules.py,README.md

Jenkinsfile

@@ -0,0 +1,6 @@
+@Library("CI_LIB") _
+
+def pipeline = new ncs.sdk_mcuboot.Main()
+
+pipeline.run(JOB_NAME)
+