- added custom spinner to use instead of imported ones

- added new empty blog post
- changed react-helmet to react-helmet-async for faster tab title change and reduced console warning
- better eslint config and corresponding warning fixes (changing let -> const, removed unused variables, etc.)
- removed redundant Router from footer
- removed ignored preload attribute value from font loading link tag in index.html

source/package.json

@@ -37,10 +37,9 @@
 		"react": "^17.0.2",
 		"react-burger-menu": "^3.0.6",
 		"react-dom": "^17.0.2",
-		"react-helmet": "^6.1.0",
+		"react-helmet-async": "^1.0.9",
 		"react-router-dom": "^5.2.0",
 		"react-scripts": "^4.0.3",
-		"react-spinners": "^0.10.6",
 		"react-tooltip": "^4.2.19",
 		"styled-components": "^5.3.0",
 		"styled-theming": "^2.2.0",