Add controller-led worker auth flow (#2413)

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>

go.sum

@@ -743,8 +743,8 @@ github.com/hashicorp/golang-lru v0.5.4 h1:YDjusn29QI/Das2iO9M0BHnIbxPeyuCHsjMW+l
 github.com/hashicorp/golang-lru v0.5.4/go.mod h1:iADmTwqILo4mZ8BN3D2Q6+9jd8WM5uGBxy+E8yxSoD4=
 github.com/hashicorp/hcl v1.0.0 h1:0Anlzjpi4vEasTeNFn2mLJgTSwt0+6sfsiTG8qcWGx4=
 github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
-github.com/hashicorp/nodeenrollment v0.1.13 h1:h830EbaWqt1wyRi3DERDtUHLW3tXl4cLfbVkPeD5Twc=
-github.com/hashicorp/nodeenrollment v0.1.13/go.mod h1:LIPKi+g0g/vl3xhpbzugCalHSxX1PMeqnatkAsxRgyM=
+github.com/hashicorp/nodeenrollment v0.1.16 h1:TZ+lN7uvkW733OZE25Wo1FgkC0zwcQo1eo3NtEnHLkw=
+github.com/hashicorp/nodeenrollment v0.1.16/go.mod h1:N5gYsm8mWiDfIw/j+1IQ6NBO1cWCmhPpvQ9GB1QUnsU=
 github.com/hashicorp/vault/api v1.3.1 h1:pkDkcgTh47PRjY1NEFeofqR4W/HkNUi9qIakESO2aRM=
 github.com/hashicorp/vault/api v1.3.1/go.mod h1:QeJoWxMFt+MsuWcYhmwRLwKEXrjwAFFywzhptMsTIUw=
 github.com/hashicorp/vault/sdk v0.1.13/go.mod h1:B+hVj7TpuQY1Y/GPbCpffmgd+tSEwvhkWnjtSYCaS2M=