[stable-5] Deprecate collection (#624)

[Andersson007]

• Deprecate collection

• Deprecate content in meta/runtime.yml

• Update documentation

• alternatives -> alternative

(cherry picked from commit f2c35544d327c6d837ecb78a6392d3c1228b7508)

SUMMARY

Manual backport of https://github.com/ansible-collections/community.network/pull/624

[Andersson007]

the only conflict was in README, so will merge it after the CI has passed