Added missing file for oauth 2.0

[harikrishna-patnala]

In the OAuth documentation, registration image is missing

https://docs.cloudstack.apache.org/en/4.19.1.0/adminguide/accounts.html#using-oauth2-authentication-for-users

Added that file in this PR.

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📚 Documentation preview 📚: https://cloudstack-documentation--417.org.readthedocs.build/en/417/

[harikrishna-patnala]

@blueorangutan docbuild

[blueorangutan]

@harikrishna-patnala a Jenkins job has been kicked to build the document. I'll keep you posted as I make progress.

[blueorangutan]

QA-Doc build preview: https://qa.cloudstack.cloud/builds/docs-build/pr/417. (QA-JID 246)

[harikrishna-patnala]

@blueorangutan docbuild

[blueorangutan]

@harikrishna-patnala a Jenkins job has been kicked to build the document. I'll keep you posted as I make progress.

[blueorangutan]

QA-Doc build preview: https://qa.cloudstack.cloud/builds/docs-build/pr/417. (QA-JID 247)

[DaanHoogland]

@harikrishna-patnala , this looks a bit awkward:

is it possible to make the spacing between the elements better?

[DaanHoogland]

@harikrishna-patnala if this is possible I think it is ready for merge.