feat: Introduce build env image pipeline (#27189)

server/build/Dockerfile.buildenv

@@ -1,3 +1,5 @@
 FROM golang:1.21.8-bullseye@sha256:81d98548f08e22a59c5c0be814acc0997f3dfd3313487adcf4e1d3d962af3a43
 
-RUN apt-get update && apt-get install -y make git apt-transport-https ca-certificates curl software-properties-common build-essential zip xmlsec1 jq
+RUN apt-get update && apt-get install -y make git apt-transport-https ca-certificates curl software-properties-common build-essential zip xmlsec1 jq pgloader
+
+RUN git config --global --add safe.directory /mattermost