Enhance Import/Export.

**What is the current behaviour and why should it be changed?**

Jamulus uses an .ini file to save session and configuration information. However for one who wishes to use different context or computers, the same Jamulus.ini file cannot be re-used without manual editing, which is not recommended.

Currently Import /Export functionality only allows the transfer of `

**Describe possible approaches**

A solution would be to add the `

**Has this feature been discussed and generally agreed?**

Discussion/Technical Suport & Help : Copy jamulus.ini from Windows unto Linux ? #2807

Start by locating Jamulus's existing Import/Export handling for jamulus.ini and compare how statements are processed with statements. Review the context in issue #2807, then verify that importing and exporting preserves the relevant IP address entries without breaking existing files.

Written by the indexing model from the issue text.