docs(infrastructure): operator deploy at top, dev in its own section (#335)

Restructure the provider README: the operator deploy (single-cluster
in-cluster default + separate-runtime variant, verify/upgrade/publishing) is now
the first section after the intro; all local-dev and manual/non-operator wiring
(run locally, real kro, register, build image, manual kro install, init-container
bootstrap, init env vars) moves under a '# Development' divider. Reflects the
in-cluster runtime default (single provider kubeconfig).

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: mjudeikis