add dynamic options for cache (#4894)

* add dynamic options for cache

* fixed bugs based on unit-test

* add doc for cache

* make cache implements be private

* Change simpleCache name to InMemoryCache

Signed-off-by: Wenhao Zhou <wenhaozhou@yunify.com>

* Remove fake cache and replacing to in memory cache with default parameter

Signed-off-by: Wenhao Zhou <wenhaozhou@yunify.com>

Signed-off-by: Wenhao Zhou <wenhaozhou@yunify.com>

pkg/simple/client/cache/factory.go

@@ -0,0 +1,8 @@
+package cache
+
+type CacheFactory interface {
+	// Type unique type of the cache
+	Type() string
+	// Create relevant caches by type
+	Create(options DynamicOptions, stopCh <-chan struct{}) (Interface, error)
+}