Changed characters graphql query to use the filter format, changed description for files query to match the others'

graphql/schema/root.graphql

@@ -3,8 +3,8 @@ type Query {
   # Find character by either an ID or a nick.
   character(id: String, nick: String): Character
 
-  # Find characters by either a list of ids, nicks or an author. Only one parameter at a time
-  characters(ids: [String!], nicks: [String!], author: String): [Character!]!
+  # Find characters
+  characters(filter: CharactersFilter): [Character!]!
   
 
   # Find channel by name
@@ -32,7 +32,7 @@ type Query {
   # Find file by ID
   file(id: String!): File
 
-  # Files get all available files. If includePublic is set, it will return public files as well
+  # Find files
   files(filter: FilesFilter): [File!]!