Allow user to set API Key Expiration in the API Key/End Point Overlay Interface

[petrklapka]

Based on feedback from Oleg to Vadim's preview of the new overlay interface:

"The new overlay looks great! But is there any reason you decided not to let users tweak the expiration date for their API key? It feels like there is enough space in that layout to not be too overwhelming to the user. It's a common best security practice to always let and encourage users to control the expiration date of any API key and access tokens unless there is a strong reason not to."

[elasticmachine]

Pinging @elastic/appex-sharedux (Team:SharedUX)

[kevinsweet]

@olegsu good raise, but fyi we made a decision to forgo this function from this menu. the nature of this component is "quick/easy" and there are a number of functionalities we're hiding here to make it so. The full functionality is still available from the API menu for cases where users want to customize various aspects of the API key. thanks!