Update Navigation UI for iOS

Update both Tab and Nav Bar to comply with iOS standards for the phones with a bezel (iPhone X, Xs, Xr).
Fix unique key warning in NavBarButton and PillBar.

Updated simple Notification

Update simple Notification to include the following props;

1. textColor,
2. fontSize: Either text identifier of supported font sizes or numerical value,
3. fontWeight,

Update simple Notification to edit the following props;

1. image: now an object that accepts props of the Image component from react-native.
2. icon: now an object that accepts props of the Icon atom.

Update Input, DatePicker, Picker, TextArea Atoms' style customization

Include new styles rounded and underline to all input types.
Allow user-defined styles to be used as well.
Include the feature to include a validating method, and display an error message.

Updated TabBar

Allow TabBar to have the position top for Android only.

Editable Thumbnail

Allow Thumbnail Atom to include a onEdit method, to change the image.

New Thumbnail, ThinListItem and SnackBar elements

Created new atom, Thumbnail.
Created new molecules, ThinListItem and SnackBar.
Updated Navigation organisms styles to include more customization.
Updated ListItem to include either rounded or square Thumbnails.
Updated ListView to use either ListItem or ThinListItem.
Updated Icon Atom to use all icon fonts.

Updated Navigation Elements

Updated both NavBar and TabBar elements and children to allow for more customization by the user.

New Badge Atom

Created a new Badge atom.
Render user-defined styles in most components.