Add the ability to override the namespace

[larsmaes]

What this PR does / why we need it:

This PR adds the ability to override the namespace where the flux resources are deployed in. By default it deploys to the release, but now you gain the ability to use it as a sub chart and deploy to its own namespace.

Which issue this PR fixes

fixes #239

Special notes for your reviewer:

Checklist

• DCO signed
• Chart Version bumped
• helm-docs are updated
• Helm chart is tested
• Update artifacthub.io/changes in Chart.yaml
• Run make reviewable

[thereisnotime]

I am amazed how many headaches the lack of this caused me. Who in their right mind forgot to put a configurable namespace

[mattwelke]

@thereisnotime

Normally, the --namespace option lets you set the namespace chart components will be deployed into. This issue only comes up when you use the chart as a subchart.

Let's be nice. I'm glad they've opened this PR to add support for this.

[TylerGillson]

@stefanprodan thoughts on merging this? We'd really appreciate it! 🙇🏼‍♂️

[tamalsaha]

@larsmaes are you still interested in this pr? If yes, can you please squash and rebase your pr on main branch?