A more generic way to find cached datasets

* a method to find datasets without DBSDaemon instance
* Remove dbsmgr from DASQuery
* refactor wildcard matching accordingly

fixes issue #4061
decoupled KWS from using DBSDaemon instances

* now KWSWebService do not need an instance to DASWebService anymore

fixes issue #4061
refactored; fixed wildcard tests; use exhaust=True

* refactored DBSDaemon.find_static -> find_datasets method of module
* refactored wildcards tests
* use exhaust=True
refactored a helper function to query a db/col

* created a function query_db(db, col, query, idx, limit) in DAS.utils.das_db
* no exhaust=True with limit
Merge pull request #4064 from dmwm/dbsmngr_dependencies

get rid of dependencies to Dbsmngr instances