[11.x] Added new Eloquent methods: whereDoesntHaveRelation, whereMorphDoesntHaveRelation and their variants with OR

[andrey-helldar]

Laravel offers to simplify relation queries using the whereRelation and whereMorphRelation methods, but it doesn't have opposite methods. This PR adds them:

// Before
User::whereDoesntHave('comments', function ($query) {
    $query->where('created_at', '>', now()->subDay());
})->get();

// After
User::whereDoesntHaveRelation(
    'comments', 'created_at', '>', now()->subDay()
)->get();

User::whereDoesntHaveRelation(
    'comments', 'is_approved', false
)->get();

// Before
User::whereDoesntHaveMorph('comments', [Post::class, Video::class], function ($query) {
    $query->where('created_at', '>', now()->subDay());
})->get();

// After
User::whereMorphDoesntHaveRelation(
    'comments', [Post::class, Video::class], 'created_at', '>', now()->subDay()
)->get();

User::whereMorphDoesntHaveRelation(
    'comments', [Post::class, Video::class], 'is_approved', false
)->get();