* Add signing key generation and conversion tooling

Will be used by MSC3916 implementation.

* Relicense my own utility as MIT

* also relicense canonical_json util

* appease the linter

* don't forget the relicensed test too

* Update go-singleflight-streams to handle weird EOF behaviour from minio

* Changelog

* Remove double `https:` from export URLs

* Changelog

* Factor out common functions to utilities

* Add Dendrite importer

* Factor out common setup for offline imports

* Split out archival creation

* Fix usage of the word "synapse" in common

* Add Dendrite exporter

Upgrade dependencies

Restructure `matrix` package

Don't log when there's no exif data

Update dependencies

Set a default range request chunk size

Fixes https://github.com/turt2live/matrix-media-repo/issues/468

Check user.IsShared when testing for repo admin access.

Fixes https://github.com/turt2live/matrix-media-repo/issues/485

Merge pull request #486 from turt2live/dependabot/go_modules/github.com/docker/docker-24.0.7incompatible

Bump github.com/docker/docker from 24.0.6+incompatible to 24.0.7+incompatible

Bumps [github.com/docker/docker](https://github.com/docker/docker) from 24.0.6+incompatible to 24.0.7+incompatible.
- [Release notes](https://github.com/docker/docker/releases)
- [Commits](https://github.com/docker/docker/compare/v24.0.6...v24.0.7

)

---
updated-dependencies:
- dependency-name: github.com/docker/docker
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Upgrade dependencies

Improve error handling around redis cache population on upload