Meta(dashboard): Ship Custom Dashboards

[nishantmonu51]

P0

• [x] #4311 (@djbarnwal)
• [x] #4312 (@djbarnwal, https://github.com/rilldata/rill/pull/4495)
• [x] #4314 (@ericpgreen2, https://github.com/rilldata/rill/pull/4531)
• [x] #4317 (@AdityaHegde)
• [x] #4318 (@AdityaHegde)
• [x] #4319 (@briangregoryholmes, https://github.com/rilldata/rill/pull/4249)
• [x] https://github.com/rilldata/rill/issues/4567 (@briangregoryholmes)
• [x] #4380
• [x] https://github.com/rilldata/rill/issues/4689
• [ ] Create canonical Custom Dashboard example (@mindspank)
• [ ] Documentation (@mindspank, @AndrewRTsao)
• [ ] User tests with design partners (@mindspank, @AndrewRTsao)
• [ ] Adjust Dashboard and Markdown component to the latest Chart -> Component refactor
• [x] #4851
• [ ] #4850
• [ ] Support inline component declaration in a dashboard
• [ ] #4313 (@djbarnwal, design needed)

P1

• [ ] #4378 (@briangregoryholmes)
• [ ] #4316 (@ericpgreen2)