Add additional data to participant export

[Semir1212]

Only for users with permission to "Manage users":

• First name
• Last name
• Gender
• City
• Country

[yurabakhtin]

@Semir1212 @luke- We already had "First name" and "Last name" in previous version for all users even without permission "Manage users". If we hide the columns for users without permission then only single column "Participation Status" will be exported, for me it looks strange, so I just added new columns "Gender", "City" and "Conuntry" in the PR #429.

Now it works like this for users with the permission:

"First name","Last name","Participation Status","Email","Gender","City","Country"
"David","Roberts","Attending","david.roberts@humhub.yb","","Allwood",""
"Sara","Schuster","Attending","sara.schuster@humhub.yb","male","Friedland","BE"

without the permission:

"First name","Last name","Participation Status"
"David","Roberts","Attending"
"Sara","Schuster","Attending"

Please correct me if something wrong.

[Semir1212]

@yurabakhtin You are right, thats perfect. Please just also include the username in both cases.

[yurabakhtin]

@Semir1212 Commit d3c36d8:

"Username","First name","Last name","Participation Status"
"david1986","David","Roberts","Attending"
"sara1989","Sara","Schuster","Attending"