This PR adds initial support for running Consul Connect Ingress Gateways (CIGs) in Nomad. These gateways are declared as part of a task group level service definition within the connect stanza.
```hcl
service {
connect {
gateway {
proxy {
// envoy proxy configuration
}
ingress {
// ingress-gateway configuration entry
}
}
}
}
```
A gateway can be run in `bridge` or `host` networking mode, with the caveat that host networking necessitates manually specifying the Envoy admin listener (which cannot be disabled) via the service port value.
Currently Envoy is the only supported gateway implementation in Consul, and Nomad only supports running Envoy as a gateway using the docker driver.
Aims to address #8294 and tangentially #8647
adds in oss components to support enterprise multi-vault namespace feature
upgrade specific doc on vault multi-namespaces
vault docs
update test to reflect new error
From [https://github.com/appc/spec/blob/master/spec/aci.md](https://github.com/appc/spec/blob/master/spec/aci.md):
>environment (list of objects, optional) represents the app's environment variables (ACE can append). The listed objects must have two key-value pairs: name and value. The name must consist solely of letters, digits, and underscores '_' as outlined in IEEE Std 1003.1-2008, 2016 Edition, with practical considerations dictating that the name may also include periods '.' and hyphens '-'. The value is an arbitrary string. These values are not evaluated in any way, and no substitutions are made.
Dotted environment variables are frequently used as a part of the Spring Boot pattern. (re: ZD-6116)
This PR specifically doesn't address the conversion of hyphens (`-`) due to an issue with rkt [[Nomad GH # 2358]](https://github.com/hashicorp/nomad/issues/2358).
