Add initial support of device posture checks (#1540)

This PR implements the following posture checks:

* Agent minimum version allowed
* OS minimum version allowed
* Geo-location based on connection IP

For the geo-based location, we rely on GeoLite2 databases which are free IP geolocation databases. MaxMind was tested and we provide a script that easily allows to download of all necessary files, see infrastructure_files/download-geolite2.sh.

The OpenAPI spec should extensively cover the life cycle of current version posture checks.

management/server/http/policies_handler.go

@@ -206,6 +206,10 @@ func (h *Policies) savePolicy(
 		policy.Rules = append(policy.Rules, &pr)
 	}
 
+	if req.SourcePostureChecks != nil {
+		policy.SourcePostureChecks = sourcePostureChecksToStrings(account, *req.SourcePostureChecks)
+	}
+
 	if err := h.accountManager.SavePolicy(account.Id, user.Id, &policy); err != nil {
 		util.WriteError(err, w)
 		return
@@ -284,10 +288,11 @@ func (h *Policies) GetPolicy(w http.ResponseWriter, r *http.Request) {
 func toPolicyResponse(account *server.Account, policy *server.Policy) *api.Policy {
 	cache := make(map[string]api.GroupMinimum)
 	ap := &api.Policy{
-		Id:          &policy.ID,
-		Name:        policy.Name,
-		Description: policy.Description,
-		Enabled:     policy.Enabled,
+		Id:                  &policy.ID,
+		Name:                policy.Name,
+		Description:         policy.Description,
+		Enabled:             policy.Enabled,
+		SourcePostureChecks: policy.SourcePostureChecks,
 	}
 	for _, r := range policy.Rules {
 		rID := r.ID
@@ -351,3 +356,17 @@ func groupMinimumsToStrings(account *server.Account, gm []string) []string {
 	}
 	return result
 }
+
+func sourcePostureChecksToStrings(account *server.Account, postureChecksIds []string) []string {
+	result := make([]string, 0, len(postureChecksIds))
+	for _, id := range postureChecksIds {
+		for _, postureCheck := range account.PostureChecks {
+			if id == postureCheck.ID {
+				result = append(result, id)
+				continue
+			}
+		}
+
+	}
+	return result
+}