VDB-120 include tic in dent and tend (#118)

* Add constants for TTL and tic for fakeHeader

* Add tic to tend transformer

* Update tests for tend

* Fix string conversion bug in fakes

* Fix tend integration tests after staging rebase

* Add tic to dent transformer

* Update dent tests

* Change integration tests to use hardcoded block timestamp

pkg/transformers/shared/constants/data.go

@@ -1,3 +1,6 @@
 package constants
 
 var DataItemLength = 32
+
+// TODO Grab this from DB, since it can change through governance
+var TTL = int64(10800) // 60 * 60 * 3 == 10800 seconds == 3 hours