Move to github.com/jetstack/cert-manager repo

[munnerz]

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Closes #134

Release note:

Move to 'jetstack' organisation. Action required: this will require updating your existing deployments to point to the new image repository, as new tags will not be pushed to the old 'jetstackexperimental/cert-manager-controller` repository.

/area admin
/assign
/release-note-action-required

[munnerz]

/release-note-action-required

[jetstack-bot]

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[jetstack-bot]

@munnerz PR needs rebase

[munnerz]

/approve

[jetstack-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: munnerz

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[jetstack-bot]

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions here.