add stagnant_contributions dir

[RussBerg]

stagnant_contributions is a directory intended to hold definitions that are not used but may have been used or have had development done to them.

closes #1644

[phyy-nx]

Recommendations from telco:

• Move sub folder of contributed
• Rename to dormant_contributions
• Check if the documentation will be built if these are in a sub folder
• When definitions are moved to dormant, add to them a note as to why they are there. "This application definition is dormant, we believe it is not used, and it is not planned to move into the main application definitions folder. Please contact XXX for more details." Or something like this.