Some extension resource url return 404 or 500

[amvanbaren]

Fixes #432

Added publisher displayName
Added /vscode/unpkg endpoint to VSCodeAdapter
Removed WEB_RESOURCE, instead use RESOURCE
FileResource java migration
Updated /vscode/extensionquery tests to include web resources
Added /vscode/asset tests for web resources

Testing steps

Display name and 404 status

• Update VS Code product.json:

"extensionsGallery": {
    "serviceUrl": "http://localhost:8080/vscode/gallery",
    "itemUrl": "http://localhost:8080/vscode/item",
    "resourceUrlTemplate": "http://localhost:8080/vscode/unpkg/{publisher}/{name}/{version}/{path}"
},

• Restart VS Code if it is running, to apply the changes to product.json
• Publish a couple extensions where the package.json returned 404:
  • viper-admin.viper 2.4.0
  • huacat.office-theme 1.1.3
  • PKief.material-product-icons 1.1.2
• Open developer tools in VS Code (Help > Toggle Developer Tools)
• Browse color themes in VS Code by navigating to Manage > Color Themes > + Browse Additional Color Themes...
• The color theme quick pick list should now display the publisher name as the last part of each item, e.g. ∙ viper-admin (instead of ∙ null)
• The developer tools should not contain 404 statuses for package.json files.

500 status

• Publish abelfubu.abelfubu-dark 1.3.4
• Open developer tools in VS Code (Help > Toggle Developer Tools)
• Try to get abelFubu Dark+-color-theme.json resource
• The developer tools should not contain a 500 status for http://localhost:8080/vscode/asset/abelfubu/abelfubu-dark/1.3.4/Microsoft.VisualStudio.Code.WebResources/extension/themes/abelFubu%20Dark+-color-theme.json.

[filiptronicek]

Before	After

This is for the 404s, but the 500s now work as well!

LGTM, will follow up with gitpod-io/openvscode-server#331.

[filiptronicek]

Gitpod snapshot for quick testing: https://gitpod.io#snapshot/4ab090aa-2c13-46b1-be66-a4df7a7aecda.

[jeanp413]

Awesome, thanks @amvanbaren and @filiptronicek