Add builtin Functor / Applicative / Monad

[janmasrovira]

• Depends on #2351.

Suggested Juvix implementation:

trait
type Functor (F : Type -> Type) :=
  mkFunctor {fmap : {A B : Type} -> (A -> B) -> F A -> F B};

trait
type Applicative (F : Type -> Type) :=
  mkApplicative {
    functor : Functor F;
    pure : {A : Type} -> A -> F A;
    ap : {A B : Type} -> F (A -> B) -> F A -> F B;
  };

trait
type Monad (M : Type -> Type) :=
  mkMonad {
    applicative : Applicative M;
    bind : {A B : Type} -> M A -> (A -> M B) -> M B;
  };

I've not included return in the Monad trait because it's redundant.

[jonaprieto]

Possible syntaxes discussed during the call:

• Option 1

  trait
  type Monad (M : Type -> Type) :=
  mkMonad {{applicative : Applicative M}} {
  bind : {A B : Type} -> M A -> (A -> M B) -> M B;
  };

• Option 2

  trait
  type Monad (M : Type -> Type) :=
  mkMonad  {
  {{applicative : Applicative M}};
  bind : {A B : Type} -> M A -> (A -> M B) -> M B;
  };

• Option 3

  trait
  type Monad (M : Type -> Type) :=
  mkMonad  {
  applicative : {{Applicative M}};
  bind : {A B : Type} -> M A -> (A -> M B) -> M B;
  };