Add dockerized local setup for the gc-conductor plugin

Add configuration to build Gerrit image, that includes gc-executor and
gc-conductor plugin.
Add configuration to build PostgreSQL image.
Add docker-compose.yaml to run Gerrit and PostgreSQL images build,
containers creation and start.
Add shell script docker_setup.sh to wrap docker-compose build and up
commands and initialize build parameters from command line arguments.

Feature: Issue 13098
Change-Id: I1073c8e67bdbbe449734672be8b9a0dd72ae5d4e
diff --git a/.gitignore b/.gitignore
index e5d39e2..961867f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@
 /gc-executor.jar
 /gc.config
 /startup.log
+*.iml