[iOS][Swift] Module Map File

[jwoo-msft]

What platform is your feature request related to? (Delete other platforms).

• iOS

Is your feature request related to a problem? Please describe.
Swift users can use our framework using a bridge header.
But there is a better way to share our framework with our users.

Modules improve access to the API of software libraries by replacing the textual preprocessor >> inclusion model with a more robust, more efficient semantic model. — Clang Documentation

Describe the solution you'd like
Add a module and its module map file.

[jwoo-msft]

@shalinijoshi19
Outlook's iOS client needs this support as they are moving their code base to swift.

[dalemyers]

Outlook's iOS client still needs this :)

We are almost entirely Swift now. We've had to make do by having a fork of the repo and making our own changes. We can't be the only ones who want to pull this into a pure Swift project any more.