Swagger service baseurl uses WebHostUrl if set

This allows SS responses to contain public facing base urls when behind a
reverse proxy.
Moved ToHttps to non-obsolete class

Backfilled unit tests for ToHttps method and fixed several defects
associated with it. It now only replaces http with https once and only at
the beginning of the line. Its also case insensitive.

Refactored Regex declarations to use the same PlatformRegexOptions
constant.
Prepend WebHostUrl to metadata urls if set

If the WebHostUrl config is set use that as the base url for metadata links, otherwise fallback to the previous functionality of using relative paths. This allows the metadata pages to work when behind a reverse proxy.
Fixed naming inconsistency in splitcamelcase regex