Providing workflow parameters right in a command line w/o having to create *.json files

When starting a workflow we need to be able to provide its input and meta parameters (those that correspond to **params argument of method start_workflow() which are used, for example, to pass 'task_name' for reverse workflows) right in a command line.

One of the options is to specify parameters as key-value pairs like:

mistral execution-create wf_name param1=val1 param2=val2 ....

However, we should keep in mind that we have 2 types of parameters: input params and meta params. Both are optional. And following this approach with key-value pairs we may have name conflicts between them.

So need to think about the best way how it could be solved.