Use vader for temperature linear variable change

[travissluka]

Description

similar to #924, except for the linear variable changes

• Modify the SOCA LinearVariableChange class to use VADER
• Modify the insitu T/S yaml in (e.g. 3dvar ctest) to use the generic VertInterp, and therefore use VADER
• make sure everything is working as expected!
• Remove all usage of InsituTemperature observation operator in the ctests, and consider it deprecated
• open issues in skylab/soca-science to do the same yaml changes

Dependencies:

• https://github.com/JCSDA-internal/vader/issues/193

[travissluka]

Fyi @Dooruk, I should have a branch in soca with the changes needed "ready" to test with your Vader branch

[travissluka]

Fyi @Dooruk, I should have a branch in soca with the changes needed "ready" to test with your Vader branch

Tomorrow... I left out the word "tomorrow"