connect: set consul TLS options on envoy bootstrap

[shoenig]

Fixes #6594 #6711 #6714 #7567

e2e testing is still TBD in #6502

Before, we only passed the Nomad agent's configured Consul HTTP
address onto the consul connect envoy ... bootstrap command.
This meant any Consul setup with TLS enabled would not work with
Nomad's Connect integration.

This change now sets CLI args and Environment Variables for
configuring TLS options for communicating with Consul when doing
the envoy bootstrap, as described in
https://www.consul.io/docs/commands/connect/envoy.html#usage

[shoenig]

Demo

# consul.hcl

log_level = "INFO"

data_dir = "/tmp/consul"

server = true

bootstrap_expect = 1

advertise_addr = "127.0.0.1"

addresses {
  https = "0.0.0.0"
}

ports {
  http  = -1
  https = 8501
  grpc  = 8502
}

connect {
  enabled = true
}

verify_incoming = true

verify_outgoing = true

verify_server_hostname = true

ca_file = "consul-agent-ca.pem"

cert_file = "dc1-server-consul-0.pem"

key_file = "dc1-server-consul-0-key.pem"

auto_encrypt {
  allow_tls = true
}

# nomad.hcl
log_level = "INFO"
data_dir  = "/tmp/nomad-client"

client {
  enabled = true
}

server {
  enabled          = true
  bootstrap_expect = 1
}

consul {
  ssl        = true
  verify_ssl = false
  address    = "127.0.0.1:8501"
  ca_file    = "consul-agent-ca.pem"
  cert_file  = "dc1-client-consul-0.pem"
  key_file   = "dc1-client-consul-0-key.pem"
}

consul agent -config-file=consul.hcl

sudo nomad agent -dev-connect -config=nomad.hcl

$ nomad job init -connect -short
$ nomad job run example.nomad

The jobs don't die now!

Allocations
ID        Node ID   Task Group  Version  Desired  Status   Created    Modified
43e1856b  6211908b  dashboard   0        run      running  2m57s ago  2m45s ago
870e1426  6211908b  api         0        run      running  2m57s ago  2m45s ago

[tgross]

LGTM 👍

[github-actions]

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