Allow expressing `meta` and `env` blocks as map attributes as well.
`env` and `meta` should support arbitrary key and values, yet hcl2
restricts the keys to valid identifiers. For example, block attribute
identifiers may not contain dots, `.`, which frequently used in meta
fields, and sometimes in environment variable fields.
This change attempts to parse `env`/`meta` both as an attribute and as a
block.
This additionally allows better expressivity for env/meta blocks, using
functions. For example, one can reuse a set of environment variables for
multiple tasks, using a local common_envs value:
```hcl
env = merge(local.common_envs, {"more_env_key", "..."})
```
state store: call-out to generic update of job recommendations from job update method
recommendations API work, and http endpoint errors for OSS
support for scaling polices in task block of job spec
add query filters for ScalingPolicy list endpoint
command: nomad scaling policy list: added -job and -type
