This diff updates the Dagit "solid sidebar":
- More clearly differentiate the current invocation and the solid definition by splitting the sidebar apart into two sections.
- Add an "Invocations" tab which shows you all the invocations in the current pipeline and allows you to click to jump to another instance.
- Make the collapsible headings "sticky" so you can opt to permanently hide Invocations, for example, or jump between invocations without the view resetting.
- Font sizes in the sidebar are a bit more consistent.
This diff also addresses the issues we had with handle IDs vs solid names. The URL bar is now solid names, not solid handles:
This fixes an issue that prevented clicking to navigate to another solid in the sidebar. In general in Dagit, the methods that allow you to focus / expand, etc. a particular solid all take either a solid name or a solid path, which is generated by splitting a handle.