Prettify and improve stabilities

1. [Feature] Prettify counsel-imenu.
2. [Feature] Save and load frame parameters (size & position).
3. [Feature] New Option: centaur-server.
4. [Optimize] don't display icons it too many items in dired.
5. [Feature] New option `centaur-icon': Display icons or not.
6. [Feature] Support fullscreen while recovering frame.
7. [Doc] Introduce the minimal configurations.
8. [Feature] Auto select the fastest ELPA mirror at the first startup.
9. [Feature] Save theme option to custom.el.
10. [Feature] Auto theme: theme-switching based on daytime
11. [Feature] Load random theme.
12. [Feature] New option `centaur-lsp-format-on-save-ignore-modes'.
13. [Enhancement] Improve forge topic list.
14. [Feature] Better yasnippet integration in company.
15. [Enhancement] Improve icons in dired, ibuffer, ivy and treemacs.
16. Add org-roam.
17. Bug fixes and other improvements.