Introduce `set_bind` and associated lemmas + set_bind theory: revise setoid rewriting

This is @dfrumin's !383 (closed) (with authorship preserved) + some tweaks to setoid rewriting:

• strengthen set_bind_subset to have the same arity
• add missing Params instance to prevent slow failures in setoid rewriting
• Proper instances can be proven before set_bind_ext via set_solver.
• set_bind_ext is then provable by set_solver directly.

I originally sent dfrumin/coq-stdpp!1 (closed) to be added into !383 (closed), but maybe it's easier with this MR? @robbertkrebbers up to you.

theories/fin_sets.v

@@ -467,7 +467,7 @@ Section set_bind.
   Global Instance set_bind_proper : Proper (pointwise_relation _ (≡) ==> (≡) ==> (≡)) set_bind.
   Proof. unfold pointwise_relation; intros f1 f2 Hf X1 X2 HX. set_solver. Qed.
 
-  Global Instance set_bind_subset : Proper (pointwise_relation _ (⊆) ==> (⊆) ==> (⊆)) set_bind.
+  Global Instance set_bind_mono : Proper (pointwise_relation _ (⊆) ==> (⊆) ==> (⊆)) set_bind.
   Proof. unfold pointwise_relation; intros f1 f2 Hf X1 X2 HX. set_solver. Qed.
 
   Lemma set_bind_ext (f g : A → SB) (X Y : C) :