* Add confirmation step for email changes

This adds a confirmation step for email changes of existing users.
Like the initial account confirmation, a confirmation link is sent
to the new address.

Additionally, a notification is sent to the existing address when
the change is initiated. This message includes instruction to reset
the password immediately or to contact the instance admin if the
change was not initiated by the account owner.

Fixes #3871

* Add review fixes

Inspired by a user who received the email confirmation in Gmail's spam folder. This happened with Sparkpost correctly setup.

* Make Reporting admin section translatable

And translate it into english and french

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

* Make subject of emails translatable and improve french translation

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

* Make error pages translatable and translate them in english and french

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

* Translate site setting section

* Insert instance in registration emails and improve them a bit

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

* update faq with default language

* update translation for about page

* update Minio config

Thanks to @Gargon for helping me. I hope this will help others as well

* update import and export translation

* translate emails to finnish

* add finnish translation for emails

* add finnish translation for emails

* add finnish translation

* add missing dot

* update finnish language to emails

* add finnish translation for emails

* add dot and fix typo

* updated some minor typos

* remove language change due breaking emails

And by dev request

* updated minio config by dev request

* updated about page translation

* fix for Amazon S3/Minio instance setups

If you were using S3 or Minio for your files, this will fix the Import issue :)

* update translation according to issue #1515

See issue #1515

* update translation for issue #1515

see issue #1515

Fix #68