Vendor apply.DryRun

[manno]

Fleet's helmdeployer used the wranger/apply module to do a "DryRun" to find modified objects.
Apply is very configurable, however Fleet only used a specific set of options. The relevant code paths to build the "plan" have been copied into the "deployer" packager. Several options, parameters, interfaces and switches have been removed.

• copy helmdeployer's pkgs from wrangler
• summary, had to move to the API pkg, as API cannot import fleet
• apply "patcher" was always replaced with an "append" function, patchers were never used
• delete is never used since ErrReplaced is never returned
• two structs implement "Apply" for the sugared interface, we only need
  one as "apply" is embedded in "desiredset"
• "original" is never used in patches
• rename applied package to desiredset
• fix/exclude linter warnings
• remove context from struct, pass in context directly
• replace logrus debug messages and increase verbosity

Notes

• this affects how detect drift finds deleted resources
• this affects how modified resources are detected
• the patch: field is populated by the "dryrun" code, but always overwritten by the "diff" code. It's only calculated to fill the plan.Update struct. That struct is similar to the plan.Objects' struct and Diffalready skips non modified resources. Data structures are different enough to make an optimization complicated, though. So removingplan.Update` is not part of this PR.

  modifiedStatus:
  - apiVersion: v1
    kind: ConfigMap
    name: test-simple-manifest-config
    namespace: simple
    patch: '{"data":{"test":"value"}}'

[p-se]

lgtm