[CHORE]: Move css to static\styles.css

[Vyvy-vi]

Chore Request

Describe the work

Extract CSS from templates/index.html file into a separate CSS file in static\ folder, fetch the same via link rel="spreadsheet"

iris-flower-classifier/templates/index.html

Lines 16 to 26 in 7f52296

	<style>
	.error-message {
	color: red;
	}
	.error input {
	box-shadow: 0 0 3px #cc0000;
	}
	.valid input {
	box-shadow: 0 0 3px #36cc00;
	}
	</style>

Additional information

Ref: https://fastapi.tiangolo.com/advanced/templates/?h=css#templates-and-static-files