MacOS Signed Installer

LMMS on MacOS is distributed in DMG format, which is a simple, drag-and-drop process for installation.

Unfortunately, the software icon will not run when first installed unless you Right Click, Open. This is due to [Gatekeeper](https://support.apple.com/en-us/HT202491).


The way to fix this is to become a certified Apple developer and then [sign our executable using an Apple certificate](https://cmake.org/cmake/help/v3.2/module/CPackBundle.html#variable:CPACK_BUNDLE_APPLE_CERT_APP). For a standard business to become a "developer" this requires a [D&B background check ](http://www.dnb.com) to validate identity. We operate similar to a business, but we're technically not, putting us in a Catch-22. This is a fairly common problem with open source projects such as LMMS as the developers are generally individuals and not a specific organizational entity.

Our first attempt is to reach out to Apple for a sponsored Developer Account. We've successfully gained sponsorship through NetworkRedux for our EV1 hosting package (normally hundreds USD/mo) as well as sponsored SSL certificate, so the idea of sponsorship isn't completely crazy. So... I've already reached out to sales and they provided this phone number `ODAwLTYzMy0yMTUy(base64)` to contact Apple Development team directly.

If this hits a dead-end, I personally would be willing to sponsor the developer account myself (about $100 USD/year), but it would be for a single individual (such as myself) instead of for the organization. This would be reflected in the certificate itself (which isn't normally displayed to the end-user on Apple).

The issue names CPackBundle and CPACK_BUNDLE_APPLE_CERT_APP but no repository files or tests. Start by reviewing the CPackBundle signing configuration and Apple sponsorship or account requirements; done means a distributed macOS DMG launches without requiring Right Click, Open.

Written by the indexing model from the issue text.