closes #8178

Due to a bug in Rails, .truncate returns a frozen string if the string actually changed, but not if there are no changes. This leads to inconsistent behaviour, and broken tests.

This was fixed upstream, see https://github.com/rails/rails/pull/36109, but the fix did not make it into 5.2.x, so we have to work around for the time being.

It doesn't add any security to have this encrypted, but it adds
complexity for podmins, because they need to backup the key.

closes #8014

closes #7932

When people only write `https://` as image URL, this would fail with
`Addressable::URI::InvalidURIError: Absolute URI missing hierarchical segment: 'https://'`.

closes #7922

Facebook removed the API and facebook integration is broken now, so lets
remove it.

closes #7874

Otherwise camo crashes with:
TypeError [ERR_UNESCAPED_CHARACTERS]: Request path contains unescaped characters

closes #7871

/ was missing in the profile entity $ref

closes #7835

LinksController redirects requests for provided diaspora:// links to
respective entities urls.

This adds a new dependency (`libidn11-dev` on debian, I'm not sure about
other distros).

This reverts commit 070e4caa.

Fixes #7695.

closes #7777

This feature only worked on the same pod and was more confusing than
useful.

closes #7718

This can be used in later diaspora versions to order the profile updates
so we don't overwrite a newer profile with older data.

This is to let the author of the post know, that this pod is interested
in updates about this post.

The sending user is only used to verify that the participation was sent
from this pod, but lets use an admin/podmin account if available.

closes #7708

fixes #7701
closes #7702

closes #7683

Fixes #7651

closes #7652

[ci skip]

closes #7646

closes #7641

closes #7639

This uses a lot of memory for big accounts. Also it doesn't make much
sense to rollback everything when something fails, it's better to delete
everything we can.

- Removed posts and non contacts from other's data
- Collections are exported in batches to lower memory footprint
- In base exporters create User object instead of keeping instance because it caches all associations

closes #7627

closes #7595

closes #7605

This was in all stack traces, which confused people ...

We currently only support IE11, so the version check was already old
again ...

When we break old browser versions, we don't check that for other
browsers. So older IE browser just break, like very other older browser
too.

closes #7557