Fix Publisher and skip signing where SHA2 unsupported

Signing service only supports signing with SHA2 so we can't
sign VSIXs where VS does not support it (namely: VS2010, VS2012
VS2013).

Tag templates for discovery in VS2019 New Project dialog

Merge pull request wixtoolset#12 from wixtoolset/rob/votive-for-2019

Prepare for Votive v1

Rebase pull request to close wixtoolset#9 from 'drolevar/fixes'

Merge pull request wixtoolset#6 from robmen/wix311-template-fixes

Fix WiX v3.11 templates

Merge pull request wixtoolset#5 from robmen/branded-logos

Brand logo images and try larger images to look better on VS Marketplace

Merge pull request wixtoolset#2 from robmen/v311-prerc-fixes

V311 prerc fixes