Add the Option to Define Default Backing Store by the User Explicitly

[shirady]

Is your feature request related to a problem? Please describe.
Not a problem, an improvement.

Describe the solution you'd like
I want to have an explicit command to define the default resource in the CLI (and in the operator in general).

Describe alternatives you've considered

1. Leave it as is, today I used an RPC call update_account_s3_access to change the default resource.
2. Create another RPC call that is quite similar to update_account_s3_access just more simple (email and default_resource as required fields only) and with a meaningful name.
3. Have an explicit command to define the default resource.

[shirady]

After I talked with @dannyzaken:

1. Moving this issue to the core repo.
2. We don't create RPC calls for every specific use. Instead, we will remove the required field of s3_access - the use of it was historical: before the UI was deprecated we had two types of accounts account UI and account access S3, account UI was for using the UI and it didn't have s3_access. Today, all of our accounts have it.

[nimrod-becker]

@dannyzaken how does this differ from the work on the default BS ?

[dannyzaken]

Closing this issue after discussing with @shirady. there is not real need to change the API right now. changing the default resource can be done by the CLI with NooobaaAccount CR