Move DAE initialization imports/exports to top level of OrdinaryDiffEqCore

- Move imports and exports from initialize_dae.jl to OrdinaryDiffEqCore.jl
- Follows the pattern of having all imports/exports at the subpackage top level

Author: ChrisRackauckas

lib/OrdinaryDiffEqCore/src/OrdinaryDiffEqCore.jl

@@ -27,6 +27,10 @@ import FastPower: fastpower
 import SciMLBase: solve!, step!, isadaptive
 import DiffEqBase: initialize!
 
+# DAE Initialization algorithms
+import DiffEqBase: DefaultInit, ShampineCollocationInit, BrownFullBasicInit
+export DefaultInit, ShampineCollocationInit, BrownFullBasicInit
+
 # Internal utils
 import DiffEqBase: ODE_DEFAULT_NORM,
                    ODE_DEFAULT_ISOUTOFDOMAIN, ODE_DEFAULT_PROG_MESSAGE,

lib/OrdinaryDiffEqCore/src/initialize_dae.jl

@@ -1,9 +1,3 @@
-# Import all initialization algorithms from DiffEqBase
-import DiffEqBase: DefaultInit, ShampineCollocationInit, BrownFullBasicInit
-
-# Re-export for convenience
-export DefaultInit, ShampineCollocationInit, BrownFullBasicInit
-
 ## Notes
 
 #=