Move upred to algebra as it is not tied to the Iris logic.

_CoqProject

@@ -49,7 +49,7 @@ algebra/agree.v
 algebra/excl.v
 algebra/iprod.v
 algebra/functor.v
-program_logic/upred.v
+algebra/upred.v
 program_logic/model.v
 program_logic/adequacy.v
 program_logic/hoare_lifting.v

heap_lang/tests.v

 (** This file is essentially a bunch of testcases. *)
-Require Import program_logic.upred program_logic.ownership.
+Require Import program_logic.ownership.
 Require Import heap_lang.lifting heap_lang.sugar.
 Import heap_lang uPred notations.
 

program_logic/model.v

-Require Export program_logic.upred program_logic.resources.
+Require Export algebra.upred program_logic.resources.
 Require Import algebra.cofe_solver.
 
 (* The Iris program logic is parametrized by a functor from the category of