Add option to store contacts inside apps data

[W1zardK1ng]

Checklist

• I am using the latest version - x.xx.x
• I checked, but didn't find any duplicates (open OR closed) of this issue in the repo.
• This issue contains only one feature request. I will open one issue for every feature I want to request.

Describe the feature you want

Add an option to store contatcs under the apps own storage, so that Koler app can work without accessing the contacts stored int he phone.

Is your feature request related to a problem? Please describe it

Andoid doesnot have a per app basis contact permission setup, some apps wont work without giving it contact permission.
If we want to isolate contacts, current option is to use apps like Open contacts or simple contacts.
while Simple contact can work with simple dialer to display the caller name for contacts stored inside the apps own storage, its a bit complicated setup. Koler simplify it just by adding an own contacts storage section.

Additional context

Simple contact app has a option to store contacts to apps own storage so no other apps can see the contacts stored here but all other simple apps can use it, Koler simplyfy this if it can have a own space to store the contacts.

How will you/everyone benefit from this feature?

This option will help eveyone to have a separate contact database and which is isolated from other apps. Also every time someone call it shows the contacts names.