Add initial templating support to Vault credential libraries
This adds support for templating various account and user values into
Vault dynamic credential library POST bodies and GET/POST paths.
It also unifies how parameters are used in grants, with backwards
compatibility.
This adds an action to the API that allows pulling out an activation
token that can be given to a worker in its config (directly or via env
or file). The worker can pass this along with its normal request in
place of its normal nonce and the server will automatically accept it.
Co-authored-by: Irena Rindos <irenarindos@users.noreply.github.com>
Ashlee M Boyer
Jeff Mitchell
