Add a pre-commit hook to check for signed-off commits

[nfnt]

What this PR does / why we need it:
In addition to #1164 this adds a commit hook configuration for pre-commit to check for signed-off commits.

$ git commit -s
golangci-lint........................................(no files to check)Skipped
signed-off-commits.......................................................Passed

[kensipe]

I find that I'm against this. we need to talk as a team regarding this

[kensipe]

this new process has many open questions to be answered...
like Co-authored-by: needs to be last lines in the the commit message... now we have
Signed-off-by: which also needs to be last lines. Do they work together?

If the sign-off is missing... does any committer sign off on it?

There is NO value to the sign-off for committers (it is for patches). Why would we require our internal team to sign-off on something that we already know they are in agreement with (DCO) with a token that is used for other purposes. Why would we change their workflow with something that doesn't add any value?

I'm strongly opposed to this

[nfnt]

Closing this, as we need to decide on our approach first.

[nfnt]

Reopening, as we're now enforcing DCO and this hook can be helpful if enabled.