closes #180

webfinger: send JRD by default instead of XRD

See merge request pleroma/pleroma!211

JRD being the default representation for WebFinger responses was standardized 5 years ago in
RFC 7033.

webfinger: refactor webfinger() functions

Closes #212

See merge request pleroma/pleroma!210

- remove code duplication
- move user lookup to parent with statement
- tighten both user lookup by nickname and activitypub URI with a type constraint

Proposal: Default Avatar Replacement

See merge request pleroma/pleroma!209

Dedupe uploads

See merge request pleroma/pleroma!115

MastoAPI: Add streaming for lists.

See merge request pleroma/pleroma!183

locked accounts

See merge request pleroma/pleroma!180

Nginx Config - Security Upgrades

See merge request pleroma/pleroma!207

* Added OCSP Stapling
* Added SSL Cache
* Changed ciphers
* Specified ECDH curves

* Removed TLSv1 and TLSv1.1
* Added OCSP Stapling
* Added SSL Cache
* Changed ciphers
* Specified ECDH curves

activitypub transmogrifier: accept/reject outgoing: we might send the actual object instead of the URI in some cases, handle it

this was caused by lack of Undo follows in the early days, and can likely be eventually removed

activitypub: when unfollowing, update the follow activity's disposition to 'cancelled' so it cannot be reused