vsce: Debug task should launch server from deploy dir

[t1m0thyj]

Currently a number of steps are required to test server changes in the VSCE:

• build server binaries
• download PAX artifact
• deploy new server

Investigate how to make the VSCE use the deploy dir in config.local.json when launched in debug mode.

Perhaps we could have the VSCE check the ZOWE_OPT_SERVER env var and define it in tasks.json like this: https://stackoverflow.com/a/67321906/5504760