Add HashiCorp Nomad provider (#483)

* provider: adding Nomad provider

* updating CONTRIBUTING.md with Nomad provider

* updated README.md by adding the Nomad provider

* fix typo

* adding nomad/api and nomad/testutil deps

* adding Nomad binary dependency for provider tests

* fixed the nomad binary download command step and added tolerations to the nomad provider.

* adding nomad provider demo gif

* adding my name to authors

* adding two missing go-rootcerts files after dep ensure

* delete pod comment

vendor/github.com/hashicorp/go-sockaddr/ipaddrs.go

@@ -0,0 +1,98 @@
+package sockaddr
+
+import "bytes"
+
+type IPAddrs []IPAddr
+
+func (s IPAddrs) Len() int      { return len(s) }
+func (s IPAddrs) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+
+// // SortIPAddrsByCmp is a type that satisfies sort.Interface and can be used
+// // by the routines in this package.  The SortIPAddrsByCmp type is used to
+// // sort IPAddrs by Cmp()
+// type SortIPAddrsByCmp struct{ IPAddrs }
+
+// // Less reports whether the element with index i should sort before the
+// // element with index j.
+// func (s SortIPAddrsByCmp) Less(i, j int) bool {
+// 	// Sort by Type, then address, then port number.
+// 	return Less(s.IPAddrs[i], s.IPAddrs[j])
+// }
+
+// SortIPAddrsBySpecificMaskLen is a type that satisfies sort.Interface and
+// can be used by the routines in this package.  The
+// SortIPAddrsBySpecificMaskLen type is used to sort IPAddrs by smallest
+// network (most specific to largest network).
+type SortIPAddrsByNetworkSize struct{ IPAddrs }
+
+// Less reports whether the element with index i should sort before the
+// element with index j.
+func (s SortIPAddrsByNetworkSize) Less(i, j int) bool {
+	// Sort masks with a larger binary value (i.e. fewer hosts per network
+	// prefix) after masks with a smaller value (larger number of hosts per
+	// prefix).
+	switch bytes.Compare([]byte(*s.IPAddrs[i].NetIPMask()), []byte(*s.IPAddrs[j].NetIPMask())) {
+	case 0:
+		// Fall through to the second test if the net.IPMasks are the
+		// same.
+		break
+	case 1:
+		return true
+	case -1:
+		return false
+	default:
+		panic("bad, m'kay?")
+	}
+
+	// Sort IPs based on the length (i.e. prefer IPv4 over IPv6).
+	iLen := len(*s.IPAddrs[i].NetIP())
+	jLen := len(*s.IPAddrs[j].NetIP())
+	if iLen != jLen {
+		return iLen > jLen
+	}
+
+	// Sort IPs based on their network address from lowest to highest.
+	switch bytes.Compare(s.IPAddrs[i].NetIPNet().IP, s.IPAddrs[j].NetIPNet().IP) {
+	case 0:
+		break
+	case 1:
+		return false
+	case -1:
+		return true
+	default:
+		panic("lol wut?")
+	}
+
+	// If a host does not have a port set, it always sorts after hosts
+	// that have a port (e.g. a host with a /32 and port number is more
+	// specific and should sort first over a host with a /32 but no port
+	// set).
+	if s.IPAddrs[i].IPPort() == 0 || s.IPAddrs[j].IPPort() == 0 {
+		return false
+	}
+	return s.IPAddrs[i].IPPort() < s.IPAddrs[j].IPPort()
+}
+
+// SortIPAddrsBySpecificMaskLen is a type that satisfies sort.Interface and
+// can be used by the routines in this package.  The
+// SortIPAddrsBySpecificMaskLen type is used to sort IPAddrs by smallest
+// network (most specific to largest network).
+type SortIPAddrsBySpecificMaskLen struct{ IPAddrs }
+
+// Less reports whether the element with index i should sort before the
+// element with index j.
+func (s SortIPAddrsBySpecificMaskLen) Less(i, j int) bool {
+	return s.IPAddrs[i].Maskbits() > s.IPAddrs[j].Maskbits()
+}
+
+// SortIPAddrsByBroadMaskLen is a type that satisfies sort.Interface and can
+// be used by the routines in this package.  The SortIPAddrsByBroadMaskLen
+// type is used to sort IPAddrs by largest network (i.e. largest subnets
+// first).
+type SortIPAddrsByBroadMaskLen struct{ IPAddrs }
+
+// Less reports whether the element with index i should sort before the
+// element with index j.
+func (s SortIPAddrsByBroadMaskLen) Less(i, j int) bool {
+	return s.IPAddrs[i].Maskbits() < s.IPAddrs[j].Maskbits()
+}