Issue description

Currently, only Route/Service self is checked. The bound Plugins were not be checked now.
That is wrong.

https://github.com/apache/apisix/blob/master/apisix/http/router/radixtree_uri.lua#L118

In this way, when the data plane is running the plug-in, it exits abnormally due to illegal plug-in parameters.

1. use JSON schema to check the plugin, confirm the input parameters are valid.
2. set the default value of the plug-in through the JSON schema check.