* add s3 dependencly

* rewrite image uploader by aws-sdk-go

* improve backward compatibility of s3 image uploading

* set default for expires option

* remove acl and expires

change(text panel): removed rarely used (and not properly working), text mode option, closes #6389, closes #7214

feat(templating): completed work on built in template variables  and , closes #7190, refactors #7170

Fix webhook username mismatch

Fixing variable name mismatch so that the Authorization HTTP header is added to webhook notifications.

Use HTTPS instead of git to download tether-drop package

git protocol (tcp/udp/9418) is forbidden when using some corporate
proxies. HTTPS is used more widely.