* draft
* expose internal admin port and add proxy test
* update tests
* move comment
* add failure case, fix lint issues
* cleanup
* handle error
* revert changes to service interface
* address review comments
* fix merge conflict
* merge the tests so cluster is created once
* fix other test
1. Upgraded agent can inherit the persisted token and join the cluster
2. Agent token prior to upgrade is still valid after upgrade
3. Enable ACL in the agent configuration
- remove dep on consul main module
- use 'consul tls' subcommands instead of tlsutil
- use direct json config construction instead of agent/config structs
- merge libcluster and libagent packages together
- more widely use BuildContext
- get the OSS/ENT runner stuff working properly
- reduce some flakiness
- fix some correctness related to http/https API