Deploy kots and app to namespace named appslug

[screspod]

What this PR does / why we need it:

Changes the namespace of the kots and app deployment from "kotsadm" to the app's slug for new installations in V3. During upgrades, the "kotsadm" namespace is used if it exists, otherwise the app's slug.

Which issue(s) this PR fixes:

https://app.shortcut.com/replicated/story/109550/deploy-kots-and-app-to-namespace-named-appslug-instead-of-kotsadm

Does this PR require a test?

yes

Does this PR require a release note?

NONE

Does this PR require documentation?

NONE

[github-actions]

This PR has been released (on staging) and is available for download with a embedded-cluster-smoke-test-staging-app license ID.

Online Installer:

curl "https://staging.replicated.app/embedded/embedded-cluster-smoke-test-staging-app/ci/appver-dev-9c5afc3" -H "Authorization: $EC_SMOKE_TEST_LICENSE_ID" -o embedded-cluster-smoke-test-staging-app-ci.tgz

Airgap Installer (may take a few minutes before the airgap bundle is built):

curl "https://staging.replicated.app/embedded/embedded-cluster-smoke-test-staging-app/ci-airgap/appver-dev-9c5afc3?airgap=true" -H "Authorization: $EC_SMOKE_TEST_LICENSE_ID" -o embedded-cluster-smoke-test-staging-app-ci.tgz

Happy debugging!

[screspod]

added this to address a golangci-lint error in Sanitize