fix:#48 Add loading animations

[apikmeister]

Issue

Adding loading spinners or animations

Changes made

• Add loading animation

• Add not found state

Resolves #48

[dk-a-dev]

@apikmeister we have added flutter lint rules with a new commit, please pull that commit and make sure to optimise and refactor your code before putting up any commits as per lint rules, your code editor will help u out in code improvement, by giving warnings make sure to fix them, pull and checkout once and commit necessary changes then I will merge ur pr If u need help in sorting out these conflicts feel free to reach-me-out