docs: adjust flags to options in cobra help and usage template

[fabianburth]

What this PR does / why we need it

Renames the Flags section in --help to Options. The Synopsis currently shows ocm [<options>] ..., with referring to the command line options listed under Flags. This might confuse users (or at least concern if something does not work).

Before:

> ocm get component --help
ocm get componentversions — Get Component Version

Synopsis:
  ocm get componentversions [<options>] {<component-reference>}

Aliases:
  componentversions, componentversion, cv, components, component, comps, comp, c

Flags:
  -c, --constraints constraints   version constraint
  -h, --help                      help for componentversions
      --latest                    restrict component versions to latest
      --lookup stringArray        repository name or spec for closure lookup fallback
  -o, --output string             output mode (JSON, json, tree, wide, yaml)
  -r, --recursive                 follow component reference nesting
      --repo string               repository name or spec
  -S, --scheme string             schema version
  -s, --sort stringArray          sort fields

Now:

> ocm get component --help
ocm get componentversions — Get Component Version

Synopsis:
  ocm get componentversions [<options>] {<component-reference>}

Aliases:
  componentversions, componentversion, cv, components, component, comps, comp, c

Options:
  -c, --constraints constraints   version constraint
  -h, --help                      help for componentversions
      --latest                    restrict component versions to latest
      --lookup stringArray        repository name or spec for closure lookup fallback
  -o, --output string             output mode (JSON, json, tree, wide, yaml)
  -r, --recursive                 follow component reference nesting
      --repo string               repository name or spec
  -S, --scheme string             schema version
  -s, --sort stringArray          sort fields

Which issue(s) this PR fixes

#1189

[morri-son]

lgtm