clean up styles a bit

[atherdon]

• https://github.com/GroceriStar/react-native-shoppin-list/blob/master/src/Main.js#L6

• https://github.com/GroceriStar/react-native-shoppin-list/blob/master/src/components/layouts/AddValueToList.js#L25-L42

• https://github.com/GroceriStar/react-native-shoppin-list/blob/master/src/components/layouts/CreateIngredientsList.js#L76-L145

• https://github.com/GroceriStar/react-native-shoppin-list/blob/master/src/components/layouts/CreateNewGrocry.js#L26-L46

• https://github.com/GroceriStar/react-native-shoppin-list/blob/master/src/components/layouts/IngredientDetails.js#L119-L146

• https://github.com/GroceriStar/react-native-shoppin-list/blob/master/src/components/layouts/Todo.js#L61

• https://github.com/GroceriStar/react-native-shoppin-list/blob/master/src/components/layouts/index.js#L49-L57

• https://github.com/GroceriStar/react-native-shoppin-list/blob/master/src/components/layouts/introSlider.js#L9-L17

• https://github.com/GroceriStar/react-native-shoppin-list/blob/master/src/components/layouts/introSlider.js#L26

• https://github.com/GroceriStar/react-native-shoppin-list/blob/master/src/components/layouts/introSlider.js#L33

• https://github.com/GroceriStar/react-native-shoppin-list/blob/master/src/components/layouts/introSlider.js#L47-L55

Fix for each checkbox should be a separated commit, in order to not break things that other developer working on

[atherdon]

more about styles can be read here: https://www.reactnative.guide/8-styling/8.3-separating-styles-from-component.html
https://facebook.github.io/react-native/docs/stylesheet
https://medium.com/mindorks/everything-to-know-about-styling-in-react-native-7e30aed53ad