Add Website Preview plugin

[Junhao-Han]

Adds Website Preview, a generic OJS plugin for previewing static website projects submitted as ZIP files from the OJS workflow page.

The plugin registers a Web Project file type, adds a Website preview action in the workflow, selects a clear index.html entry point, and renders the project in a sandboxed preview frame.

Tested against OJS 3.3.0-21.

[asmecher]

@Junhao-Han, thanks for submitting! At a glance, the tests directory contains some potentially dangerous scripts. If these are invoked via the web server by guessing the URL, they can have unexpected consequences. I would suggest using PHPUnit-style tests, which are encapsulated in classes. Alternately, you can exclude those from the plugin package (if you're using the build tool described in the plugin guide, you can list files/paths to exclude in an exclusions.txt file in the plugin repo).

[Junhao-Han]

@asmecher, thanks for the review. I converted the archive tests from a directly executable smoke script into a PHPUnit-style test class, so the test file no longer performs actions if reached through the web server.

I published a new plugin release, 1.0.0.1, and updated this PR to point to the new package and MD5. The updated package contains tests/WebsitePreviewArchiveServiceTest.php instead of the previous executable smoke script.

[asmecher]

Thanks, @Junhao-Han, I've merged the plugin!

[Junhao-Han]

Thank you very much, @asmecher !