Add Swift Package Manager support

[ChrisPearce]

It would be very helpful if Swift Package Manager was supported by including a Package.swift file.
AB#7068

[MIchaelMainer]

We think this is a great idea but we currently don't have resources to work on this.

[pascalfriedrich]

Would be great! It's my last dependency in podfile ;-)

[alak]

It will become really important to support SPM (most of the other libraries already support it (aka facebook, google etc..))

It's 2023 and still no support for SPM. Not even latest carthage support