feat: create Firebase AI quickstart

[thatfiredev]

CI will fail at the moment, since the SDK has not been released yet. I will make sure it's green after the SDK is released and only merge by then.

Fast follows:

• Add a Function calling example
• Add a Stream Realtime example

[marinacoelho]

Suggestion: create color variables in Color.kt and add the transparency using hex color code.

[thatfiredev]

The backgroundColor property here is dynamic and it changes according to the color set at the OS-level, so it can't really be hardcoded into Color.kt.

    val backgroundColor = when (chatMessage.role) {
        "user" -> MaterialTheme.colorScheme.tertiaryContainer
        else -> MaterialTheme.colorScheme.secondaryContainer
    }

[marinacoelho]

This is looking very good! Just left a few comments (not all of them are blockers). We should also add a README before merging it :)