Escher auth encode "reserved character" on query params

the “reserved characters” defined by RFC3986 (Uniform Resource Identifier) have to be kept as they are (no encoding applied)
The code currently encode everything (refering to https://github.com/emartech/escher-java/blob/96eacf0ead41cad72f388a4de31d9dabc501f525/src/main/java/com/emarsys/escher/Helper.java and to the function "private String queryParameterToString(NameValuePair entry)"




