Enable restricted network builds

[smuda]

Description

When building the grafana operator from source within a network restricted environment, being able to use local images and GOPROXY/GOPRIVATE is a requirement.

Relevant issues/tickets

#707

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• This change requires a documentation update
• I have added tests that prove my fix is effective or that my feature works
• I have added a test case that will be used to verify my changes
• Verified independently on a cluster by reviewer

Verification steps

[NissesSenap]

The error seems to be related to: hadolint/hadolint#339

This seems like a okay workaround to define it in
ARGS instead of in the definiton: hadolint/hadolint#339 (comment)

What do you think @smuda ?

[smuda]

@NissesSenap You are probably right, well found! I've moved the default values to the top which also makes it more readable. At the same time I also rebased on top of the current HEAD from master.

To make sure images can be replaced I ran the following command and verified the output contained the new images:

$ docker build \
  --build-arg BUILDER_IMAGE=golang:1.18 \
  --build-arg UBI_MINIMAL_IMAGE=registry.access.redhat.com/ubi8/ubi-minimal:8.5 \
  --build-arg UBI_MICRO_IMAGE=registry.access.redhat.com/ubi8/ubi-micro:8.5 . 

To make sure GOPROXY can be replaced I ran the following command and watched as the network traffic did go the direct route to the dependencies:

docker build --build-arg GOPROXY=direct --build-arg GOPRIVATE=github.com . 

[pb82]

@smuda this looks good, only needs a rebase

[smuda]

@pb82 I rebased on top of master.

[NissesSenap]

LGTM, sorry for the delay and thanks for the help @smuda