feat: Hmac access

[vkamlov]

Hi there!
In this PR I would like to add the possibility of granting HMAC access to service accounts. This will be useful for people, who want to create access to buckets using access keys and secret keys.
If you see what can be better here, feel free to add your changes

[google-cla]

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[vkamlov]

Changed author and committer info, for passing CLA

[vkamlov]

Can someone check this PR? There aren't a lot of changes, only adding a little functionality

[bharathkkb]

Thanks for the PR @vkamlov and sorry for the delay

[vkamlov]

@bharathkkb could you review it again?

[comment-bot-dev]

@vkamlov
Thanks for the PR! 🚀
✅ Lint checks have passed.

[vkamlov]

Why do the int and lint checks don't execute?

[apeabody]

/gcbrun

[apeabody]

Why do the int and lint checks don't execute?

Thanks for the contribution @vkamlov. A maintainer needs to trigger the CI, which I just did for the most recent commit.

[apeabody]

/gcbrun

[vkamlov]

Thanks!
Can you merge my changes if everything will be ok?

[apeabody]

Thanks for the contribution @vkamlov!

[apeabody]

Thanks! Can you merge my changes if everything will be ok?

Looks good, done!

[vkamlov]

A lot of thanks!