Simplify export method in importexport.py

[ironmaniiith]

For more reference see this discussion: #50 (comment)

[ironmaniiith]

@djay , I think I've found the reason why this behaviour existed in the very first place. So the way the current export happens is, we check a bunch of checkboxes and select which all fields to have in the metadata. In these checkboxes options, 'type', 'id', 'uid', and 'path' are not there, but seems like they are a necessary component if we have to support an import functionality for the existing content.
Can you clear if this was the reason why you implemented it in this way @Shriyanshagro ?
If this is the case, then maybe we can keep this appending the mandatory fields for now and can think about this PR later.

[djay]

@ironmaniiith its a misunderstanding of the original requirements. The system is meant for 2 purposes. import/export within plone and import/export with external systems. What you use as a primary key will depend on the purpose. All fields should be optional but with sensible defaults.
Also I think its simpler to have id and path be the same thing since the id is in the path.