Add ACL auto bootstrapping option

[angrycub]

This enables Nomad to start and bootstrap the ACL subsystem without having to run the nomad acl bootstrap command separately. This does require a certain amount of post-deployment hygeine around removing these values after using them in bootstrap.

The primary usecases for this being

• Facilitating starting debugger-built binaries in ACL-enabled mode when performing interactive debugging
• Reducing complexity of e2e tests that require ACL-enabled clusters

[tgross]

Ref: https://hashicorp.atlassian.net/browse/NET-10379