Remove deprecated operator code

Author: ChrisRackauckas

src/SciMLBase.jl

@@ -575,21 +575,6 @@ $(TYPEDEF)
 abstract type AbstractSensitivitySolution{T, N, S} <: AbstractTimeseriesSolution{T, N, S} end
 
 # Misc
-# TODO - deprecate AbstractDiffEqOperator family
-"""
-$(TYPEDEF)
-"""
-abstract type AbstractDiffEqOperator{T} <: AbstractSciMLOperator{T} end
-
-"""
-$(TYPEDEF)
-"""
-abstract type AbstractDiffEqLinearOperator{T} <: AbstractDiffEqOperator{T} end
-
-"""
-$(TYPEDEF)
-"""
-abstract type AbstractDiffEqCompositeOperator{T} <: AbstractDiffEqLinearOperator{T} end
 
 """
 $(TYPEDEF)
@@ -720,10 +705,6 @@ $(TYPEDEF)
 abstract type AbstractParameterizedFunction{iip} <: AbstractODEFunction{iip} end
 
 include("retcodes.jl")
-include("operators/operators.jl")
-include("operators/basic_operators.jl")
-include("operators/diffeq_operator.jl")
-include("operators/common_defaults.jl")
 include("symbolic_utils.jl")
 include("performance_warnings.jl")
 
@@ -853,10 +834,6 @@ export EnsembleAnalysis, EnsembleSummary
 
 export tuples, intervals, TimeChoiceIterator
 
-export AffineDiffEqOperator, DiffEqScaledOperator
-
-export DiffEqScalar, DiffEqArrayOperator, DiffEqIdentity
-
 export step!, deleteat!, addat!, get_tmp_cache,
        full_cache, user_cache, u_cache, du_cache,
        rand_cache, ratenoise_cache,