Fix #1298: Text input support on AlertPopupView

[jamesmudgett]

Adds text input support for AlertPopupView. Supports all input(keyboard) types and secure input as well. Example usage:

let popup = AlertPopupView(image: #imageLiteral(resourceName: "browser_lock_popup"), title: "PIN verification required", message: "", inputType: .asciiCapable, secureInput: true, inputPlaceholder: "Enter your Yubikey PIN")

        popup.addButton(title: "Cancel") { () -> PopupViewDismissType in
            return .flyDown
        }

        popup.addButton(title: "Verify", type: .primary) { [weak self] () -> PopupViewDismissType in
            guard let pin = popup.text else { return .deny }

            // ...more error handling.
            if pin.isEmpty {
                return .deny
            }

            print(pin)

            return .flyUp
        }
        browserLockPopup = popup
        popup.showWithType(showType: .flyUp)

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• My patch or PR title has a standard commit message that looks like Fix #123: This fixes the shattered coffee cup! (or No Bug: <message> if no relevant ticket)
• Unit Tests are updated to cover new or changed functionality
• User-facing strings use NSLocalizableString()
• New files have MPL-2.0 license header.

Test Plan:

Screenshots:

Reviewer Checklist:

• PR is linked to an issue via Zenhub.
• Issues are assigned to at least one epic.
• Issues include necessary QA labels:
  • QA/(Yes|No)
  • release-notes/(include|exclude)
  • bug / enhancement
• Necessary security reviews have taken place.
• Adequate test coverage exists to prevent regressions.
• Adequate test plan exists for QA to validate (if applicable)

[iccub]

Few code style comments

[iccub]

add let textField = textField here to avoid unwrappings

[jamesmudgett]

Not needed here with change to use Then framework.

[iccub]

Remove public, it's needed only in frameworks

[iccub]

It would be best to not version this package-lock.json file at all for this PR

[jhreis]

lgtm. @jamesmudgett in future please make sure to complete the PR template submitter checklist.

@iccub feel free to merge if you approve it, please just verify the squashed message, as it may not be correct by default.