add Redis cache and some clean up

- update and cleanup in README.md
- update getIdentity to throw response exception with 401 in JwtService
- update http files to use identity from env
- add cacheable to getIdentityFromDevice in DeviceRegistryService
- add RedisCacheConfiguration
- add CacheProperty
- set up cache property
- set up data redis cache

src/test/resources/application.yml

@@ -6,3 +6,5 @@ device-data:
   url: http://localhost:9020
 device-configuration:
   url: http://localhost:9030
+cache:
+  time-to-live: 10