deactivate stack- digest check N/A

[s1cyan]

Change the digest check to say N/A if the stack gets deactivated. Currently it just says unknown which we have found can be from a number of causes

Kabanero Instance Stacks    Version Status  Valid Digest
-------------------------   ------- ------  ------------
java-microprofile       0.2.26  active  matched
java-openliberty        0.2.3   active  matched
java-spring-boot2       0.3.28  inactive unknown
nodejs              0.3.3   inactive unknown
nodejs-express          0.2.10  inactive unknown

[davco01a]

merged