consul: add support for service weight

[mvegter]

Manual verification

No `weights`

$ curl -s http://127.0.0.1:8500/v1/agent/services  | jq '.[] | select(.Service=="global-redis-check") | .Weights'
{
  "Passing": 1,
  "Warning": 1
}

---

weights {}

$ ./bin/nomad job plan ./job.hcl
+/- Job: "redis"
+/- Task Group: "cache" (1 in-place update)
  +/- Task: "redis" (forces in-place update)
    +/- Service {
        Address:           ""
        ...
      + Weights {
        + Passing: "1"
        + Warning: "1"
        }
        }

$ curl -s http://127.0.0.1:8500/v1/agent/services  | jq '.[] | select(.Service=="global-redis-check") | .Weights'
{
  "Passing": 1,
  "Warning": 1
}	

---

weights {
  passing = 5
}

$ ./bin/nomad job plan ./job.hcl
+/- Job: "redis"
+/- Task Group: "cache" (1 in-place update)
  +/- Task: "redis" (forces in-place update)
    +/- Service {
          Address:           ""
          ...
      +/- Weights {
        +/- Passing: "1" => "5"
            Warning: "1"
          }
        }

$ curl -s http://127.0.0.1:8500/v1/agent/services  | jq '.[] | select(.Service=="global-redis-check") | .Weights'
{
  "Passing": 5,
  "Warning": 1
}

[mvegter]

=== NAME  TestVaultCompat/testVaultVersions
    vaultcompat_test.go:326: download: installing vault at /tmp/vault-bins/1.18.0
    vaultcompat_test.go:332: 
        vaultcompat_test.go:332: expected nil error
        ↪ error: exit status 1
        ↪ PostScript | annotation ↷
        	failed to download vault 1.18.0: hc-install: will install vault@1.18.0
        failed to install vault@1.18.0: unexpected Content-Type: "application/vnd+hashicorp.releases-api.v1+json"

Seems like CI is flaky here, unrelated to the changeset