Feature Request - Plax CLI should error out if you send a Plaxt test request without supplying all the parameters required in a test

Plax should return an error if a plax test contains variables that are not defined / supplied in the plax test run command.

For example, a test may contain a section like this:

payload:
url: '{?!HOSTANDPORT}/api/{?!ACCOUNTID}?userid={?!USERID}'
method: GET

If you then send the plax test run command without supplying those variables, the test currently runs and fails without an error explaining that those variables weren't defined.

Bad request that should produce an error:
`plax -test get-account.yaml -p '?!HOSTANDPORT=http://localhost:9090' -log debug`

Properly formatted request:
`plax -test get-account.yaml -p '?!HOSTANDPORT=http://localhost:9090' -p '?!ACCOUNTID'='12345abcde' -p '?!USERID'='test-users' -log debug`