Feature/cd air craft star

[chengdang]

Description

This PR contains some of the recent updates to CRTM delivered by STAR https://github.com/JCSDA/CRTMv3/tree/CloudRadar_AirCraft, including:

• Downward ADA calculation
• Updated Aircraft level calculation (upwelling radiance at user-defined pressure level)
• New optional feature for computing downwelling radiance at user-defined pressure level.
• *The radar updates will be addressed in a separate PR.

Notes:

• All updates are for forward calculation only. TL, ADA, K-matrix code development under testing.
• A new unit test has been added, see issue Create unit tests for aircraft level/downward ADA calculations  #158
• Some of the build file updates can probably be ignored or removed (files under folder src/Build/), given the recent updates to CRTM build system.

Dependencies

None

Impact

Expect changes to CRTM forward results at aircraft level
More scientific validation is needed.

Checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have run the unit tests before creating the PR