This PR adds pid_mode and ipc_mode options to the exec and java task
driver config options. By default these will defer to the default_pid_mode
and default_ipc_mode agent plugin options created in #9969. Setting
these values to "host" mode disables isolation for the task. Doing so
is not recommended, but may be necessary to support legacy job configurations.

Closes #9970

drivers/exec+java: Add configuration to restore previous PID/IPC namespace behavior

Co-authored-by: Chris Baker <1675087+cgbaker@users.noreply.github.com>

Co-authored-by: Chris Baker <1675087+cgbaker@users.noreply.github.com>

Co-authored-by: Chris Baker <1675087+cgbaker@users.noreply.github.com>

Co-authored-by: Chris Baker <1675087+cgbaker@users.noreply.github.com>

Co-authored-by: Chris Baker <1675087+cgbaker@users.noreply.github.com>

Co-authored-by: Chris Baker <1675087+cgbaker@users.noreply.github.com>

This PR adds default_pid_mode and default_ipc_mode options to the exec and java
task drivers. By default these will default to "private" mode, enabling PID and
IPC isolation for tasks. Setting them to "host" mode disables isolation. Doing
so is not recommended, but may be necessary to support legacy job configurations.

Closes #9969

The details of host volume and CSI volume requests do not show up in `nomad
plan` outputs, although the updates are detected by the scheduler and result
in an update as expected.

This closes #9966. It was looking at the query parameters
for the namespace and region, but allocation (and task!)
routes don’t have a namespace query parameter. Since the URL
generator requires the job for all calls, it makes sense to
extract the namespace and region from the job instead.

add prefix-search and auto-completion for `scaling policy info` command

- aws secret key is named incorrectly in the target docs.
  It needs to match what is in the nomad-autoscaler repo
  (see link below), otherwise the autoscaler will default to AWS sdk
  behavior, which could end up using an IAM instance profile
  or other environment variables instead of what is passed into the
  autoscaler config file.

Ref: https://github.com/hashicorp/nomad-autoscaler/blob/e60fb5268d2107ab18e2be11e5d438fedc3eb2a8/plugins/builtin/target/aws-asg/plugin/plugin.go#L27

drivers/docker: support mapping multiple host ports to the same container port

This changes the Babel compilation targets to exclude IE 11,
which results in significant payload size savings.

UI: Cross region server monitor

e2e packer build: upgrade jdk to java 14

scheduler: add tests and fix for detected host_network and to port field changes

This includes seemingly-unrelated changes because of dependency updates.

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.

By adding attribute syntax support, we maintain backward compatibility and relax the block attribute key restrictions. This change attempts to parse `env`/`meta` both as an attribute and as a
block.

Additionally, the change allows better expressivity for env/meta blocks, using
functions and for expressions. 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", "..."})
```

Note that the map/attribute compatibility workaround is currently a pattern we recommend for driver config blocks: https://www.nomadproject.io/docs/job-specification/hcl2#blocks . :( Sadly, the document isn't accurate, as only `meta` appearing inside driver config was handled in 1.0.1.

Closes https://github.com/hashicorp/nomad/issues/9606

As pointed out by Nick Ethier, if a node was ineligible before
it went down, downness should be displayed, not ineligibility.

The region will naturally be appended to URLs via
token.authorizedRequest but agent members includes all servers across
all regions so relying on the application-level region isn't good
enough.