Improve Component architecture/bound component documentation

[filbabic]

A user reported they didn't realise our bound components (powered by ViewModels) require a start() call and they were stuck a bit on an empty screen.

We added start() functions to help users control over the lifecycle of our ViewModels. Based on their feedback, we should make sure we call the start() function in some of our bound components (so they don't have to) and/or that we add more guidance in the documentation, showing people they should call start() themselves.

Action points:

• [x] Improve our documentation for bound components
• [x] Add default start() calls where possible

[filbabic]

Let's just move to starting by default and removing the start() function by default.

If our users require this level of granulation, we can re-introduce it with more control (like autoStart flags in the constructor).