Interface
Common
```kotlin
interface SelectableDates
```
An interface that controls the selectable dates and years in the date pickers UI.
## Functions
isSelectableDate
```kotlin
fun isSelectableDate(utcTimeMillis: Long) = true
```
Returns true if the date item representing the `utcTimeMillis` should be enabled for
selection in the UI.
isSelectableYear
```kotlin
fun isSelectableYear(year: Int) = true
```
Returns true if a given `year` should be enabled for selection in the UI. When a year is
defined as non selectable, all the dates in that year will also be non selectable.