performance: Keep request counts low and transfer sizes small

[ychoy]

According to this audit report from Chrome Dev Tools, this can be enhanced to improve performance:

To set budgets for the quantity and size of page resources, add a budget.json file. Learn more. https://developers.google.com/web/tools/lighthouse/audits/budgets?utm_source=lighthouse&utm_medium=devtools

Resource Type	Requests	Transfer Size
Total	39	8,234 KB
Image	19	6,457 KB
Script	8	1,643 KB
Font	6	72 KB
Stylesheet	2	44 KB
Document	2	17 KB
Other	2	1 KB
Media	0	0 KB
Third-party	22	820 KB