Callr Actions editor: latest versions first, documentation in the editor

The Callr Actions editor of the Console makes the current versions of the actions easier to find.

Latest versions first. In the documentation panel of the editor, the latest version of each action has a latest tag. Previous versions are hidden; turn on Show previous versions to see them. The choice is remembered by your browser.
Clearer panel. The documentation panel is split into Concepts (expressions, variables, branches, conditions, goto, defaults) and Actions, with alternating rows.
Documentation while you type. Hovering an action or a parameter shows its documentation, and the auto-completion suggests ready-to-use snippets. Deprecated actions are flagged with a message pointing to their replacement.
Templates on the latest versions. Every template of the Console uses the latest version of each action (play@v3, gather@v4, recognize@v3, amd@v3, dial@v2, bridge@v3, fetch@v3, openai@v3). Scenarios created from a template before this change keep working as they are.
Fix: an expression is now accepted in the url of a voicebot@v1 tool (for example url: ${{ $url }}/search). The editor used to flag it as an error, although it worked.
Changelog is now linked from the help menu of the Console.