Improve CSV upload and error handling from qlkube

[QcFe]

Description

This PR solves several issues with the uploading procedure for CSV imports and tries to make error reporting more user friendly.

Added a few reviewers just to let them know, feel free to have a look or anything.

[kingmakerbot]

Hi @QcFe. Thanks for your PR.

I am @kingmakerbot. You can interact with me issuing a slash command in the first line of a comment. Currently, I understand the following commands:

• /rebase: Rebase this PR onto the master branch
• /merge: Merge this PR into the master branch
• /hold: Adds hold label to prevent merging with /merge
• /unhold: Removes the hold label to allow merging with /merge
• /deploy-staging: Deploy a staging environment to test this PR (the build-all flag enables user environments building)
• /undeploy-staging: Manually undeploy the staging environment

Make sure this PR appears in the CrownLabs changelog, adding one of the following labels:

• kind/breaking: :boom: Breaking Change
• kind/feature: :rocket: New Feature
• kind/bug: :bug: Bug Fix
• kind/cleanup: :broom: Code Refactoring
• kind/docs: :memo: Documentation

[QcFe]

/deploy-staging

[kingmakerbot]

Your staging environment has been correctly deployed/updated! Available here: Frontend, Qlkube Operators: add the crownlabs.polito.it/operator-selector=staging-818 label to your tenant.

[QcFe]

/deploy-staging

[kingmakerbot]

Your staging environment has been correctly deployed/updated! Available here: Frontend, Qlkube Operators: add the crownlabs.polito.it/operator-selector=staging-818 label to your tenant.

[QcFe]

/merge

[kingmakerbot]

Your staging environment has been correctly teared-down!