Co-authored-by: Sam BC <samuel.balbirnie-cumming@xdesign.com>

Fixed grammatical error in first paragraph

Reference mastodon/chart in the deployment section

* Update nvmrc to Node.js 16

* Update package.json minimum Node engine to 16

* Update README requirements to Node.js 16

* Update devcontainer Node.js version to 16

* Update devcontainer Dockerfile Node.js choices to LTS versions that are still in support/maintenance

* Pin CircleCI Node image to 16

* Fix YAML type issue

* Update CircleCI Node.js to 16.18 to match #22019

As pointed out by https://github.com/mastodon/mastodon/pull/21297#discussion_r1028372193
at least one of our dependencies already dropped support for Ruby 2.6, and we
had removed Ruby 2.6 tests from the CI over a year ago (#16861).

So stop advertising Ruby 2.6 support, bump targeted version, and drop some
compatibility code.

* Drop support for Ruby v2.5 and Node.js v12

* Update package.json

Less ass, more assets.

- Add rake task for generating Apple/Android icons and favicons from SVG
- Add rake task for generating PNG icons and logos for e-mails from SVG
- Remove obsolete Microsoft icons and configuration
- Remove PWA shortcut icons

* Bump version to 3.5.0rc1

* Various fixes and improvements

* Update AUTHORS.md

* Various fixes and improvements

* Update README.md

This is documented in the Vagrantfile, but not in the README. As far as I know,
following the short guide without installing this plugin will not make the
container accessible at mastodon.local, thus breaking the last step of the
guide.

* Modify syntax

* Change ** bold to ### header

* Revert license edit

* Change references to tootsuite/mastodon to mastodon/mastodon

* Remove obsolete test fixture

* Replace occurrences of tootsuite/mastodon with mastodon/mastodon in CHANGELOG

And a few other places

Freenode was taken over by a different entity, and former Freenode
staff created LiberaChat.

Short summary of the situation: https://blog.bofh.it/debian/id_461

With more details:

* https://gist.github.com/joepie91/df80d8d36cd9d1bde46ba018af497409
* https://gist.github.com/aaronmdjones/1a9a93ded5b7d162c3f58bdd66b8f491