enhance blog

[nichtsam]

• [x] the code is a bit messy...
• [x] better meta
• [x] better post preview in blog home
• [ ] support more content source, ex. Remotely from Github.
• [ ] pinned post
• [ ] categories and tags
• [ ] search by title, categories and tags.

[nichtsam]

yo try this out https://github.com/thinkmill/keystatic