Add _SASPROGRAMDIR macro variable

[smorrisj]

Is your feature request related to a problem? Please describe.
Request to add _SASPROGRAMDIR macro variable to our existing set.

Describe the solution you'd like
When a user sas file is executed, we'd like to have access to the directory that the file is running in, via a macro variable named _SASPROGRAMDIR. If the path to my sas file is /test/myfile.sas, then I would expect _SASPROGRAMDIR to have the value /test. This would be super useful in having the ability to use relative links.

[cjdinger]

I saw this referenced in another issue, but also a macro var that identifies the client app would be useful. We have customers who want to adapt their programs to be aware that they are running in VS Code.

EG does this:

GLOBAL _CLIENTAPP 'SAS Enterprise Guide'
GLOBAL _CLIENTAPPABBREV EG

[snlwih]

When these macro variables get implemented, we should try to address #762 (add appname when starting a SAS server connection) at the same time. Btw. that entry also talks about generating macro variables to represent both product name and clientapp version number, similar how that is done in SAS Studio.

[engmtcdrm]

I saw this referenced in another issue, but also a macro var that identifies the client app would be useful. We have customers who want to adapt their programs to be aware that they are running in VS Code.

EG does this:

GLOBAL _CLIENTAPP 'SAS Enterprise Guide'
GLOBAL _CLIENTAPPABBREV EG

This could be implemented by prepending macro variable declarations in the autoexec object of the payload prior to calling the Viya REST call to start the job. Should be pretty easy to do that plus merge any user autoexec entries as well. Probably could do something similar for this _SASPROGAMDIR too.

There are two spots where you can specify autoexec lines when starting up a Compute session/job. I'm not sure which one is being used in the code.
https://developer.sas.com/rest-apis/compute/createSession
https://developer.sas.com/rest-apis/compute/createJob