feat(datetime): add calendar picker (#23416)

resolves #19423

BREAKING CHANGE: The `ion-datetime` component has been revamped to use a new calendar style. As a result, some APIs have been removed. See https://github.com/ionic-team/ionic-framework/blob/master/BREAKING.md for more details.

core/src/components/button/readme.md

@@ -365,6 +365,10 @@ export default defineComponent({
 
 ## Dependencies
 
+### Used by
+
+ - [ion-datetime](../datetime)
+
 ### Depends on
 
 - [ion-ripple-effect](../ripple-effect)
@@ -373,6 +377,7 @@ export default defineComponent({
 ```mermaid
 graph TD;
   ion-button --> ion-ripple-effect
+  ion-datetime --> ion-button
   style ion-button fill:#f9f,stroke:#333,stroke-width:4px
 ```