Support gitattributes for correct encoding in web editor

Web editor and web IDE supposes all files are encoded in utf8. There are many files that are not. GitLab should support common ways to specify file encoding including .gitattributes and .editorconfig

Proposal

GitLab should detect the encoding of files in the Web IDE and Web Editor in the following order:

1. .gitattributes using the encoding field
2. .editorconfig using the charset field

Links

• .gitattributes encoding
• EditorConfig can help to do that