Add better explanation for cache status

- Clarify default settings for cache-read-only
- Explain why cache was disabled or read-only
- Provide links to documentation in Job Summary

Fixes #255

sources/src/caching/caches.ts

@@ -1,5 +1,5 @@
 import * as core from '@actions/core'
-import {CacheListener} from './cache-reporting'
+import {CacheListener, EXISTING_GRADLE_HOME} from './cache-reporting'
 import {GradleUserHomeCache} from './gradle-user-home-cache'
 import {CacheCleaner} from './cache-cleaner'
 import {DaemonController} from '../daemon-controller'
@@ -26,7 +26,7 @@ export async function restore(
         core.info('Cache is disabled: will not restore state from previous builds.')
         // Initialize the Gradle User Home even when caching is disabled.
         gradleStateCache.init()
-        cacheListener.cacheDisabled = true
+        cacheListener.setDisabled()
         return
     }
 
@@ -35,8 +35,7 @@ export async function restore(
             core.info('Gradle User Home already exists: will not restore from cache.')
             // Initialize pre-existing Gradle User Home.
             gradleStateCache.init()
-            cacheListener.cacheDisabled = true
-            cacheListener.cacheDisabledReason = 'disabled due to pre-existing Gradle User Home'
+            cacheListener.setDisabled(EXISTING_GRADLE_HOME)
             return
         }
         core.info('Gradle User Home already exists: will overwrite with cached contents.')
@@ -48,7 +47,7 @@ export async function restore(
 
     if (cacheConfig.isCacheWriteOnly()) {
         core.info('Cache is write-only: will not restore from cache.')
-        cacheListener.cacheWriteOnly = true
+        cacheListener.setWriteOnly()
         return
     }
 
@@ -82,7 +81,7 @@ export async function save(
 
     if (cacheConfig.isCacheReadOnly()) {
         core.info('Cache is read-only: will not save state for use in subsequent builds.')
-        cacheListener.cacheReadOnly = true
+        cacheListener.setReadOnly()
         return
     }