Generate a self signed cert on ds creation/update (#6024)

* Generate a self signed cert on ds creation/update

* Added nil check for example urls, fixed test that was failing

* updated per comments

* fixed tests

* more test fixing

* added default cert verification test

* added default cert config to cdn.conf

* updated gofmt

* added nil check

* added default cert config validation and updated db tx use
8 files changed