Have all Params objects adhere to json.Marshaler/Unmarshaler

api/params.go

cmix/gateway/hostPool.go

cmix/identity/receptionID/store/unknownRounds.go

cmix/message/params.go

cmix/params.go

cmix/pickup/params.go

cmix/rounds/params.go

connect/connect.go

e2e/params.go

e2e/ratchet/partner/session/params.go

e2e/rekey/params.go

e2e/rekey/params_test.go

fileTransfer2/connect/params.go

fileTransfer2/e2e/params.go

fileTransfer2/params.go

single/params.go