[LoadingIndicator] Add showDelay & minHideDelay attributes

[patrickfrei]

Description
The ProgressIndicator component has the following two useful features ("attributes"):

• showDelay
• minHideDelay

See the documentation.

However, these attributes are not available in the new LoadingIndicator component.

Solution request
It would be great to have these two attributes showDelay & minHideDelay available in the new LoadingIndicator component as well.