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
cskh