Added Contributor Setup guide and Podrick docforge task

[n-boshnakov]

What this PR does / why we need it:
This PR:

• Adds a Contributor Setup topic
• Adds an Issues topic
• Adds a task to help users get accustomed to working with docforge

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Release note:

Added Contributor Setup guide
Added Podrick task

[gardener-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please assign dimitar-kostadinov for approval. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[n-boshnakov]

/kind enhancement

[gardener-ci-robot]

The Gardener project currently lacks enough active contributors to adequately respond to all PRs.
This bot triages PRs according to the following rules:

• After 30d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 14d of inactivity since lifecycle/rotten was applied, the PR is closed

You can:

• Mark this PR as active with /lifecycle active
• Mark this PR as fresh with /remove-lifecycle stale
• Mark this PR as rotten with /lifecycle rotten
• Close this PR with /close

/lifecycle stale

[gardener-ci-robot]

The Gardener project currently lacks enough active contributors to adequately respond to all PRs.
This bot triages PRs according to the following rules:

• After 30d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 14d of inactivity since lifecycle/rotten was applied, the PR is closed

You can:

• Mark this PR as active with /lifecycle active
• Mark this PR as fresh with /remove-lifecycle rotten
• Close this PR with /close

/lifecycle rotten