Update api-spec for multiple stub deletion by id

[G-Basak]

References

• TODO

Submitter checklist

• The PR request is well described and justified, including the body and the references
• The PR title represents the desired changelog entry
• The repository's code style is followed (see the contributing guide)
• Test coverage that demonstrates that the change works as expected
• For new features, there's necessary documentation in this pull request or in a subsequent PR to wiremock.org

[oleg-nenashev]

@G-Basak Why is it the draft at the moment?

[G-Basak]

@G-Basak Why is it the draft at the moment?

@oleg-nenashev
A new admin api endpoint was requested in #2205.
So I created a draft for api-spec how that api will look like, before going into the full development.
Wiremock-maintainer can review this new endpoint, and share thoughts whether they would like to see this added.