Migrate from README.md to README.org (#739)

* Migrate headings and code blocks

* Migrate inline code to ~code~ notation

* Migrate most links and images

* Fix title

* cope with Github's broken headline hierarchy

* Migrate embedded html

* Migrate Headline logo and goodies/buttons

* Safer option for main logo

* Second attempt at logo+goodie formatting

* Title under logo

* Kofi Chat and other logos

* Replace <kbd> tags with =key= notation

* Capitalize BEGIN_SRC & END_SRC for consistency

* Fix html linebreak

* Fix mismatched code block

* no need to escape < > for vim keys (i.e. <leader>)

* Attempt to fix kofi icon

* One more time

* Multiple formating fixes

* More minor changes

* Add alt-text to top buttons

* Fix small formatting issues (almost complete)

* attempt to use native org checkboxes

* "Fix" checkboxes with emojis

* More emoji fixes

* Small inline code fix

* Fix small typo

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Co-authored-by: Kristijan Husak <[email protected]>