Update configkit version
Update .gitignore file
Implement AssetCache for the backend cache
Refactoring AssetConfig, AssetLoader and AssetCache
AssetEntryCluster and Cache support
Rename existing Cache to CacheFactory

Signed-off-by: c9s <yoanlin93@gmail.com>
Add __set_state support to AssetEntryCluster
Fix InitCommand
Add CacheFactoryTest
include symfony/process
more message for init command
Add tests for Asset class
Add AssetConfig tests
Method name fix: getConfig and getConfigFile
Simplify loadFromManifestFile method

- Should only accept YAML format file path.
- Rename create_collections to loadCollections
Add AssetUrlBuilder
Test collection object.
Refactoring: Construct filter objects with asset config object
remove getBaseUrl method from Asset class
Clean up