String externalization for Internationalization in SysEng-related repos

User-facing strings should not be hard coded. They should be easily externalized into resource files for review and translation into other languages. This is a major blocker to offering PE to users in their local language.

Based on the i18n guidelines created for each programming language, wrap user-facing strings in our existing code base with the appropriate string externalization function.

In scope:
Strings that appear in the GUI, reports, error and informational messages (in the GUI/CLI tools/APIs), and log entries
Comments in PE modules

Out of scope:
User-facing strings pulled in from third party software/libraries
Puppet DSL keywords
CLI tool commands
API keys
Debugging messages intended only for internal use by Puppet
Strings in code that will reach end of life by June 2017