WEBSITE_LOAD_CERTIFICATES is unused by the reference azure functions

[jamespik]

Brief description of your issue

"WEBSITE_LOAD_CERTIFICATES": "[parameters('website_load_certificates')]",
is settable by a parameter to the arm template. The setting is not actually used by the reference though, so we should remove non-meaningful options from the sample to minimize complexity.

Steps to reproduce

Expected behavior

Actual behavior

Environment