Support AWS Signature V2 for Mattermost for S3 storage. (#6462)
Support AWS Signature V2 for Mattermost for S3 storage. (#6462)

Certain S3 compatible servers only use Legacy Signature (AWS
Signature V2), current code only supports signature v4.

This PR adds facility to click a button on the UI to enable
legacy signature with S3 compatible servers.
rickbatka/mattermost-webapp,rickbatka/mattermost-webapp,rickbatka/mattermost-webapp,rickbatka/mattermost-webapp