Provide file for cFE detail design

[jphickey]

Is your feature request related to a problem? Please describe.
By default, when building cFE mission "detail design" document, the entire module directory is added to the doxygen input, which will recursively pick up all source files, but also everything else too.

This can lead to conflicts with e.g. "mainpage", where OSAL provides its own mainpage for its API guide, but this should NOT be used for other documentation that includes OSAL, like the detail design doc.

Describe the solution you'd like
OSAL should provide a detaildesign template file that indicates which sources should be used, rather than everything.

Describe alternatives you've considered
cFE itself could exclude certain parts in its templates, but that means cFE must have knowledge of OSAL directory tree.

Additional context
Related to nasa/cFE#1612

Requester Info
Joseph Hickey, Vantage Systems, Inc.

[skliper]

Could/should be generic, any higher level detailed design doxygen build could include the OSAL detailed design info. Not specific to the cFE detailed design document.