Allow user to define namespace when installing the backend applications through UI extension

[xingzhang-suse]

Description

When the user click to install applications from SSVS's installation page, it will redirect the user to the Rancher UI's installation page with given chart name, namespace and version. The namespace option is readonly in the Rancher's installation page in this case.
As of the request from product side, and also align with other UI extension's behavior, we will not pass the namespace as a query parameter when redirect to Rancher's installation page.

Attention

We need to investigate the global impact if we let user define namespace by their self.

1. Pre-creation of the namespace during create image pulling secrets
2. Predefined default namespace on any pages which are using it, like artifacts namespace in the workload scan page.

[xingzhang-suse]

The limitation of the UI workflow against the AppCo application installation workflow

Critical path before installation

The image pulling secret of each AppCo application is needed which under its namespace.

UI workflow

1. Add http secret for adding repositories of the AppCo applications
2. Duplicate the secret into image pull secret for each application with its namespace
3. Add repositories of the AppCo applications
4. Redirect to Rancher's installation page to pull and install the applications with their namespace one by one

The limitation

The namespace input requirement is before the redirection to the installation page, thus the namespace should be defined in the UI extension's page instead of letting the users select in Rancher's app installation page.

Compromised proposal

Add 3 input box to let the user type in the namespace for each application in the first step (Add secrets) instead of select it in Rancher's app installation page.

[xingzhang-suse]

The installation process with customized namespaces for each AppCo application

AppCo_installation.mov