backport: Add 8.17 branch

[elastic-vault-github-plugin-prod[bot]]

Merge as soon as 8.17 branch was created. Auto-merge is not yet supported, see https://github.com/Mergifyio/mergify-engine/discussions/2821

[mergify[bot]]

backport-8.x has been added to help with the transition to the new branch 8.x. If you don't need it please use backport-skip label and remove the backport-8.x label.

[ycombinator]

run docs-build