Nativescript: [HttpClient] Provide support for form-data with HttpClient

[NickIliev]

Is your feature request related to a problem? Please describe.
Related to:
https://discourse.nativescript.org/t/cannot-submit-formdata/5360

https://github.com/NativeScript/NativeScript/issues/59

https://stackoverflow.com/questions/53399411/nativescript-post-request-using-body-form-data

Describe the solution you'd like
Proper support for content of type multipart/form-data

Describe alternatives you've considered
Existing community plugin is providing this functionality for NativeScript Core via this plugin. We need similar functionality in the core Http module or at least for the Angular's HttpClient

[charsleysa]

@NickIliev the following pull request makes implementing this at the XHR level easier (just have to update the FormData polyfill to achieve this) https://github.com/NativeScript/NativeScript/pull/7707

[sebastiandg7]

Is there any progress on this?

[josedusol]

It would be nice to support this out of the box.