Create an wage for an employment

Activity name : <a href="https://developer.loket.nl/Activities/PostWageByEmploymentId" target="_blank">PostWageByEmploymentId</a><br><br>Create a new wage record for the given employment<br><br>Metadata : Possible options for fields of the type 'metadata' can be acquired (GET) by adding /metadata to the POST Wage URL.<br><br> <br>The possible options for payGrade are scoped by a payScale. To obtain the pay grades for a pay scale a metadata call has to be performed with the following format ../wages/metadata/payscale/{key}. Where {key} is the key of the payScale (obtained via the first metadata call) for which the pay grades are to be returned.<br><br>Defaults : Default values for a new object can be acquired by adding `/defaults' to the POST URL and performing a GET action.<br>