Persist last used namespace

[paulovmr]

Checks

• I have searched the existing issues.
• My request is related to one of the components in the kubeflow/notebooks repository.

Motivation

Every time the user access the application, a random namespace is selected, and they have to manually select the one they want to see.

Implementation

Save the last used namespace in a cookie, so the same one gets loaded once the user returns to the application.

Are you willing & able to help?

• I am able to submit a PR!
• I can help test the feature!

[thaorell]

I can take this issue

[andyatmiami]

/area v2
/area frontend

[paulovmr]

/assign @thaorell