refactor: Flatten webapi (#753)

* refactor: Flatten webapi plugin

* fix: Remove settings for testing

* refactor: Update disabled plugins in docker-network and intergration-tests

* fix: Unexport log

* fix: Upadate the imported package in consensus integration test

* fix: Fix 

* refactor: Make endpoints as subplugins

* fix: Fix 

* refactor: Rename utils.go to common.go

* refactor: Unexported api handlers

* fix: Minor fix

* refactor: Move drng/info api to drng/

* refactor: Move spammer from webapi to core plugins