K8SPG-744 Updated Contributing guide with the steps to build and deploy the Operator

[nastena1606]

CHANGE DESCRIPTION

Problem:

Contributors don't know how to build the Operator image and then deploy it to view their changes in action.

This PR extends the Contributing guide with the missing steps.

Short explanation of the problem.

Cause:
Short explanation of the root cause of the issue if applicable.

Solution:
Short explanation of the solution we are providing with this PR.

CHECKLIST

Jira

• [+] Is the Jira ticket created and referenced properly?
• [+] Does the Jira ticket have the proper statuses for documentation (Needs Doc) and QA (Needs QA)?
• [+] Does the Jira ticket link to the proper milestone (Fix Version field)?

Tests

• Is an E2E test/test case added for the new feature/change?
• Are unit tests added where appropriate?

Config/Logging/Testability

• Are all needed new/changed options added to default YAML files?
• Are all needed new/changed options added to the Helm Chart?
• Did we add proper logging messages for operator actions?
• Did we ensure compatibility with the previous version or cluster upgrade process?
• Does the change support oldest and newest supported PG version?
• Does the change support oldest and newest supported Kubernetes version?

[CLAassistant]

All committers have signed the CLA.

[gkech]

small typo: For you to help us improve, needs capital after full stop.

[gkech]

I think we have a formatting error here. E.g. the parenthesis here seems that is never opened.

[nmarukovich]

Do we want to add instructions how to run unit tests and ask contributors to add them?
@gkech wdyt?

[gkech]

Do we want to add instructions how to run unit tests and ask contributors to add them? @gkech wdyt?

I think we can catch the need for unit testing during code reviews. Also, running unit tests is generally universal in golang and even our makefile hints that. So I think it is not needed.