[#2298] Make serializer fields on OrganisationSerializer read-only
[#2298] Make serializer fields on OrganisationSerializer read-only

Looking at the client side code in the project editor, new organisations are created in steps for each model involved, so it should be OK to make the OrganisationSerializer serializer fields read-only.

akvo/akvo-rsr,akvo/akvo-rsr,akvo/akvo-rsr,akvo/akvo-rsr