feat: Add stac-browser

[alekzvik]

What I am changing

I am adding a STAC Browser as an additional service.

How I did it

I am using a custom image due to complications described here
The custom image is built on CRON once daily if there are changes.

Alternatives

Another alternative is to avoid a custom image and do all the work in the initContainer. We spawn an initContainer with node that checks out the git repo on a tag, installs dependencies, builds the stac-browser, and puts the static files in a shared volume. The main container would be nginx which serves the data from the mounted volume.
Pros:

• it is less dependent on another repo doing trickery in its actions
• it can be much more configurable

Cons:

• this approach is much slower. The npm install & npm build take a long time

Notes

1. The whole approach to the STAC browser is not ideal. I mentioned in values.yaml that the preferred way to deploy the STAC browser would not be with k8s&helm, but maybe there is a better way to convey this to users.
2. There are problems with /browser URL routing (without the trailing slash) and I have not identified the source yet.
3. The URL is persisted in a way that does not allow to recover state. If you open a collection -> item and then reload the page, stac browser fails to recover the state.

How you can test it

helm update --install ... and one more service appears in the list of static services.
The URL is /browser/, it will point to the stac endpoint exposed at /stac

Related Issues

Closes #62

[alekzvik]

Hello, this is my first contribuiton to k8s-eoapi. Please let me know if there is anything I can improve or if you prefer the alternative approach with initContainer to avoid another dependency.