Ringtone notification: split incoming calls sound notification versus other type of events

#### Is your feature request related to a problem? Please describe.
In Element-Android, there is a single setting for all sound based notifcations, like messages in private room but also incoming calls. Other applications make a distinction between the incoming call ringtone versus regular notification like receiving a text message. The lack of such distinction in Element-Android means one does not know if the sound notification is related to a incoming call or a simple message which generates frustrations as it is misleading.

#### Describe the solution you'd like.
Element-Android could allow using the system phone call ringtone for incoming calls and notification incoming ringtone for other sound based notifications. Not sure how that would work with the current UI though. Maybe split the "Notification configuration" sound selection menu single ringtone selection into 2 selections: one for incoming calls and a second one for all other notifcations

#### Describe alternatives you've considered.
None. Either the default is kept and it is confusng since the phone has a single ringtone, or no audio notifications are used at all, and one might end up missing calls.