Support function versioning

[yqf3139]

Fission supports function versioning, every function update create a new version labeled by uid.
Currently fission is missing a api for listing all the version info (timestamp, uid) for a specific function.
I have a commit to do this and is working with fission to land this.

• Add function version listing in the function edit page.
• User can replace their current working space (the draft) with any version they select.
• By default all references to a function point to it's latest version.
• Show the uid to the user of which version of code they are using for a trigger.
• Add uid selection in trigger create forms.