feat: enable v2 in the Config spec

[emosbaugh]

What this PR does / why we need it:

Adds a v2Enabled property to the embeddedcluster.replicated.com/v1beta1 Config spec can be used to opt-in to the new installer. If set, v1 installations will be migrated to v2 on upgrade. This property will be removed once the new installer is fully implemented and the old installer is removed.

Which issue(s) this PR fixes:

Does this PR require a test?

Does this PR require a release note?

Does this PR require documentation?

[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-68f86fd" -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-68f86fd?airgap=true" -H "Authorization: $EC_SMOKE_TEST_LICENSE_ID" -o embedded-cluster-smoke-test-staging-app-ci.tgz

Happy debugging!