Add option to show warnings when props could be accessed via this

Ref vuejs#1636, this is my first stab at adding an option to not treat generic access to `this` as 'using' properties / data / computed, etc. If this is the right approach, I can try adding tests if needed. It's more general I think than what you'd proposed in that issue, but for my use case it works well.

Author: dsl101

lib/rules/no-unused-properties.js

@@ -55,6 +55,8 @@ const GROUP_SETUP = 'setup'
 const GROUP_WATCHER = 'watch'
 const GROUP_EXPOSE = 'expose'
 
+const STOPREPORTING_THIS = 'ThisExpression'
+
 const PROPERTY_LABEL = {
   props: 'property',
   data: 'data',
@@ -206,7 +208,15 @@ module.exports = {
             uniqueItems: true
           },
           deepData: { type: 'boolean' },
-          ignorePublicMembers: { type: 'boolean' }
+          ignorePublicMembers: { type: 'boolean' },
+          stopReporting: {
+            type: 'array',
+            items: {
+              enum: [ STOPREPORTING_THIS ]
+            },
+            additionalItems: false,
+            uniqueItems: true
+          }
         },
         additionalProperties: false
       }
@@ -221,6 +231,7 @@ module.exports = {
     const groups = new Set(options.groups || [GROUP_PROPERTY])
     const deepData = Boolean(options.deepData)
     const ignorePublicMembers = Boolean(options.ignorePublicMembers)
+    const stopReporting = new Set(options.stopReporting || [STOPREPORTING_THIS])
 
     const propertyReferenceExtractor = definePropertyReferenceExtractor(context)
 
@@ -560,6 +571,9 @@ module.exports = {
           if (!utils.isThis(node, context)) {
             return
           }
+          if (!stopReporting.has(STOPREPORTING_THIS)) {
+            return
+          }
           const container = getVueComponentPropertiesContainer(vueData.node)
           const propertyReferences =
             propertyReferenceExtractor.extractFromExpression(node, false)