ci: Cache pre-commit installations on Jenkins Agent

This change introduces a custom helper from our shared library [0]
that defines ad-hoc container environment to execute CI steps in.

Pre-commit installation will now be cached on Jenkins Agent: builds will
tolerate network hiccups better and we will also save some run time
(although on non-critical path of a parallel process).

[0]: TrueCloudLab/jenkins#8

Change-Id: I93b01f169c457aa35f4d8bc5b90f31b31e2bd8b2
Signed-off-by: Vitaliy Potyarkin <v.potyarkin@yadro.com>

.ci/Jenkinsfile

@@ -68,12 +68,14 @@ async {
     }
 
     task('pre-commit') {
-        sh '''
-            apt update
-            apt install -y --no-install-recommends pre-commit
-        ''' // TODO: Make an OCI image for pre-commit + golang? Unpack golang tarball with a library function?
-        withEnv(['SKIP=make-lint,go-staticcheck-repo-mod,go-unit-tests,gofumpt']) {
-            sh 'pre-commit run --color=always --hook-stage=manual --all-files'
+        dockerfile("""
+            FROM ${golangDefault}
+            RUN apt update && \
+                apt install -y --no-install-recommends pre-commit
+        """) {
+            withEnv(['SKIP=make-lint,go-staticcheck-repo-mod,go-unit-tests,gofumpt']) {
+                sh 'pre-commit run --color=always --hook-stage=manual --all-files'
+            }
         }
     }
 }