handle flush_rewrite_rules more consistently

It was called in quite random places, which _might_ me the cause for
randomly breaking URLs. It’s now always handled via the transient.
include date in tracking export filename
update media files after auphonic import

fixes issue with invalid files when using auto-publish
contributors: switch real and public name fields
organize changelog entry
social: fix html-table hack & humongous paddings
fix open link for last contributor donations item
move web player settings to expert settings
move `contributor.publicemail` to social service

- add service: email
- migrate email data
- add deprecation notices
- add template accessor: `service.rawValue`
update contributor form & readme