Standalone OSAL build should export a package for use by other builds

[jphickey]

Is your feature request related to a problem? Please describe.
OSAL is not standalone software that is typically installed on a PC, but rather it is always a component that is intended to be used within a larger software application.

Currently the CMake build does work in a standalone fashion (i.e. one can invoke cmake </path/to/osal> and build the software) and the software can be compiled but the result isn't really usable for inclusion in a larger app. That is, there is no easy way for another (separate) application that needs to use OSAL to reference the headers and static library.

Describe the solution you'd like
CMake has a method for referencing a dependency through its import/export and packaging functionality described here: https://cmake.org/cmake/help/latest/guide/importing-exporting/index.html

Additional context
Note this is not necessary when building cFS - in that mode, OSAL is just included as a subdirectory within the larger build, and this should still be supported as an option for other (non-CFS) builds as well. That is, the user can simply call add_subdirectory(/path/to/osal) from their application build, and link to the provided osal library as a regular target. The export target is only useful in cases where OSAL is built as a standalone software application.

Requester Info
Joseph Hickey, Vantage Systems, Inc.