There is a section about this in the Tomcat 8 migration guide which will direct you to use a resources configuration
In particular, you will be creating a WebResourceRoot object which contains the following text in its description.
VirtualWebappLoader – Replaced by Pre- and Post-Resources mapped to WEB-INF/lib and WEB-INF/classes
Your new context.xml will look something like the following:
<Context>
<Resources className="org.apache.catalina.webresources.StandardRoot">
<PreResources className="org.apache.catalina.webresources.DirResourceSet"
base="C:\\PROJECT_NAME\\conf"
internalPath="https://stackoverflow.com/"
webAppMount="/WEB-INF/classes" />
</Resources>
</Context>