UI theme matching of the app for

[ebrain-mendoza121]

I added a folder called constants in the app code, and it has a themes file inside. It contains some basic styles that can be reusable to control the theming and styling of the app when design is in the works. It has some a mix of colors, font weights, and some shadow effects than can be used for components. If later on an official font is decided it can be added there, and have the font in bold, italic etc. The items are imported from that folder and are used in the stylesheets of the components or pages (For example: using style={{COLORS.primary}} would give the primary color of the app theme). With the file its easier to change the theme later on since it will control every component that was styled with items.