The following documentation parts were updated:
* copyright years
* stable installer urls were added
* PowerShell userdata header added (#ps1)
* Userdata types fixed
* Updated all the services config options
* Removed deprecated options for services
* Added Packet metadata service
* Added Azure metadata service
* Replaced return code with exit code in tutorial
(return code is not correct)
* Updated all the plugins config options
* Added all the undocumented plugins
* Added retry_count / retry_count_interval info
for all http based services
Change-Id: I6fdbdcaf45dec841e4080028d7d90cbbf6a6cb75
0ae70d5fe4