This is a Feature Proposal

Description

For feature proposals:

• Currently, it appears that the step function definition validation only occurs when executing sls package. This is a long executing step, and it would be easier if we could have a way to validate the step function without going through sls package.
• Recently, while writing a step function definition, I misspelled the key word "Resource" within a task definition. Although I had the validate flag set to true, the sls package command exited before it got to validate because the misspelling caused issues with the IAM role creation. This led to a long period of debugging to discover that the cause was a misspelled word, when, in theory, the validate step would have caught the problem well ahead of that stage and described the problem to us, thus saving us a lot of time.
• Barring a standalone command for validate, moving the validate check to the start of the sequence of sls package steps would be equally useful. The earlier we can get a more human readable version of potential definition errors, the better.

Additional Data

• Serverless Framework Core Version you're using: 1.46.1
• The Plugin Version you're using: 2.7.0
• Operating System: Mac OS