Fix api specs for organisations

Param group was get instead of path -- that introduced problems in
client api codegen

api/system/spec.json

@@ -381,7 +381,7 @@
       "title": "Read organisation details",
       "path": "/{id}",
       "parameters": {
-        "get": [
+        "path": [
           {
             "type": "uint64",
             "name": "id",

api/system/spec/organisation.json

@@ -89,7 +89,7 @@
       "Title": "Read organisation details",
       "Path": "/{id}",
       "Parameters": {
-        "get": [
+        "path": [
           {
             "name": "id",
             "required": true,

docs/system/README.md

@@ -465,7 +465,7 @@ Organisations represent a top-level grouping entity. There may be many organisat
 
 | Parameter | Type | Method | Description | Default | Required? |
 | --------- | ---- | ------ | ----------- | ------- | --------- |
-| id | uint64 | GET | Organisation ID | N/A | YES |
+| id | uint64 | PATH | Organisation ID | N/A | YES |
 
 ## Archive organisation
 

system/rest/request/organisation.go

@@ -287,9 +287,7 @@ func (r *OrganisationRead) Fill(req *http.Request) (err error) {
 		post[name] = string(param[0])
 	}
 
-	if val, ok := get["id"]; ok {
-		r.ID = parseUInt64(val)
-	}
+	r.ID = parseUInt64(chi.URLParam(req, "id"))
 
 	return err
 }