Any data exported by JSON Exporter does not include Security Level informations. This means that all imported data by JSON has Security Level set to 'None'. This issue also concerns importing - user cannot specify Security informations

Steps to reproduce:

1. Make sure you have a project with defined Security Levels (e.g. 'None' and 'abc-staff').
2. Create Issue A which is only visible for abc-staff
3. Create Issue B which is visible for everyone
4. Add comment to Issue B which will be visible only for abc-staff
5. List Both issues on Search screen
6. Export Issues to JSON (make sure that user who performs the export has abc-staff permissions)
7. Import exported data in step 6. to other project / other JIRA instance

Expected Version 1: Imported data in step 7. has the same security Levels that had the source issues.
Expected Version 2: Exproted data in step 6. has skipped secured Informations so they are not imported in step 7.

Actual: There is none Security-Level informations is JSON, Step 6. exports all data that is visible for the user who performs the export. Step 7. imports all data with Security Level 'None'.