[5.x] Adds typeWithPauses(), appendWithPauses() methods

[hivokas]

These methods allow you to type/append the values to the fields with pauses.

After the merging of this PR you'll be able to replace this:

->tap(function (Browser $browser) {
    foreach (str_split('+1 (202) 555-5555') as $char) {
        $browser->append('mobile', $char)->pause(100);
    }
})

With this:

->typeWithPauses('mobile', '+1 (202) 555-5555')

Motivation: #558 (comment)

[taylorotwell]

Maybe typeSlowly and appendSlowly

[hivokas]

@taylorotwell sounds good

[hivokas]

@taylorotwell I've updated the PR

[driesvints]

@hivokas can you maybe PR these to the docs?