Make winrepo package names work for pkg states

This adds a reverse name map to the repo data that is created by the
winrepo.genrepo runner, and removes some windows-specific code from the
pkg state since we no longer have to work around the fact that winrepo
packages are discovered with their full names.
Remove __context__ from get_repo_data

This is causing a traceback in the pkg state. Will have to figure out
how to fix this.
Add confirmation step for salt-key -a/-A

This implements #3495.
Remove trailing whitespace
Add example for ext_pillar in docs, Fix #5653
Merge pull request #5661 from basepi/extpillardocs

Add example for ext_pillar in docs, Fix #5653
Merge pull request #5657 from terminalmage/issue5422

Make winrepo package names work for pkg states
Merge pull request #5660 from terminalmage/issue3495

Add confirmation step for salt-key -a/-A
Document the SLS file namespace
Merge pull request #5665 from terminalmage/docs

Document the SLS file namespace
Return empty string instead of False

This fixes #5603. The return data from _pecl() is meant to be parsed
line by line, and you can't spilt a bool.
Add error message if pecl fails to run

This will log an error that might help the user troubleshoot why pecl
failed to run.
Merge pull request #5666 from terminalmage/issue5603

Return empty string instead of False