Release 5.1.0

Merge release in master

chore: bump versions

…trinuting

svetoslavtsenov/update contrinuting

…6677)

* feat(view): added iOS parameter for modal presentation style

* Now passing options to showModal in one argument

* refactor: Move context and close in modal options

* chore: Comments added for UIModalPresentationStyle.Popover case

* refactor: Use modalOptions in e2e demo

* chore: fix pbroken test

…DK (#6693)

* feat(tns-platform-declarations): Generate iOS typings from iOS 12.1 SDK

* Instructions for generating iOS typescript definitions
* Refactor `typings-gen.sh` to use {N} CLI and generate fuller
metadata for the system libraries
* Automatically generate `ios.d.ts` wrapper
* Add interop pointers and references as alternatives
to `string` for `char*` args
(implemented in NativeScript/ios-jsc#1022)

BREAKING CHANGE: Several enum values have changed because
    they have been wrongly generated.

    To migrate your app or plugin code use the new names of the
    following:
    *  enum NSUnderlineStyle:
        - `StyleNone` -> `None`
        - `StyleSingle` -> `Single`
        - `StyleThick` -> `Thick`
        - `StyleDouble` -> `Double`
     * enum AVAudioSessionErrorCode:
        - `CodeNone` -> `None`
        - `CodeMediaServicesFailed` -> `MediaServicesFailed`
        - `CodeIsBusy` -> `IsBusy`
        - `CodeIncompatibleCategory` -> `IncompatibleCategory`
        - `CodeCannotInterruptOthers` -> `CannotInterruptOthers`
        - `CodeMissingEntitlement` -> `MissingEntitlement`
        - `CodeSiriIsRecording` -> `SiriIsRecording`
        - `CodeCannotStartPlaying` -> `CannotStartPlaying`
        - `CodeCannotStartRecording` -> `CannotStartRecording`
        - `CodeBadParam` -> `BadParam`
        - `CodeResourceNotAvailable` -> `ResourceNotAvailable`
        - `CodeUnspecified` -> `Unspecified`

* fix(ui/text-base): Update NSUnderlineStyle.StyleSingle constant

After the typings regeneration its and several others' names have
changed to the expected `NSUnderlineStyle.Single`.

* fix(tns-platform-declarations): Restore deprecated enum values

In order to not introduce a breaking change in a patch version, we
are keeping `Style...` and `Code...` values that have been wrongly
generated till now. In the next major/minor release of the package
when the typings are regenerated we can safely remove them.

Revert to using the deprecated one's in `text-base.ios.ts` so that
the introduction of this breaking change doesn't slip in undetected.

* fix(application.ios): Directly call presetnNativeScriptApp

We've been using `performSelectorWithObject` but it's
declaration has been manually added. Moreover it's more
convenient to directly call the method.

…6428)

* Add a "window" value so that NS doesn't crash on selectors looking for the delegate.window...

* chore: tslint

* chore: comments to referenced issues added

…6719)