Added quick ways to open JSON Editor

[vertcitron]

Added editor title bar button and explorer context menu item.

I like your extension and I try here to bring my modest contribution.

I added two quick ways to open JSON Editor without typing the command.

• A button {} in the top right corner of the editor's title bar when a JSON file is opened in the standard editor.
• A context menu Item on right click of a JSON file in the vscode explorer.

On the context menu, if the file is not opened in a text editor, it's automatically opened alongside with JSON Editor.

The original icon was not showing well when vscode is in dark mode when in the editor title bar, I had to recreate two ones, one for light themes and one for dark themes.

I hope you'll like it...

Best regards

[gregchamblin]

I have forked this project, and implemented several of the requests and fixes. Please check it out.

https://marketplace.visualstudio.com/items?itemName=GregChamblin.vscode-json-editor