* Add cell image upload modal
* Add controller for serving the images and handle this on markdown side
* Use per-session images dir
* Add etag header to session image responses
* Adjust markdown image styling
* Properly manage session images dir
* Add tests
* Set maximum file size for image uploads
* Move images dir specifics to the Session module
* Move images when nonpersistent session becomes persistent
* Update lib/livebook_web/live/session_live.ex
Co-authored-by: José Valim <jose.valim@dashbit.co>
* Update lib/livebook_web/live/session_live.ex
Co-authored-by: José Valim <jose.valim@dashbit.co>
* Update lib/livebook_web/live/session_live/cell_upload_component.ex
Co-authored-by: José Valim <jose.valim@dashbit.co>
* Test that close gets rid of session temporary dir
Co-authored-by: José Valim <jose.valim@dashbit.co>
* Update cell actions
* Add new focus indicator
* Update headings typography
* Update cell actions and insert buttons
* Add sidebar menu
* Add settings modal
* Update homepage
* Update settings dialog
* Rename classes
* Add floating menu
* Update icon colors on hover
* Fix homepage tests
* Format assets source
* Update monaco editor
* Fix editor width on resize
* Add more padding to the notebook content
* Update settings dialog title
* Show reevaluate button when the cell is in evaluated state
* Show section actions on focus or hover only
* Pre-fill runtime selector with the current configuration
* Ignore cmd + enter in Markdown cells
* Basic filesystem navigation
* Add file picker modal
* Implement autosave when dirty and show the status
* Add hompage link in the session view
* Improve file picker and use in both places
* Move session list to homepage
* Some refactoring
* Show import messages if any
* Fix and extend tests
* Show a message when there are no sessions running
* Rename import to fork and make that clear in notebook name
* Fix old route
* Show info when no file is connected to the given session
* Show runtime type next to filename
* Show button for joining session when a running path is selected
* Move modal components to SessionLive namespace
* Add FileGuard to lock files used for notebook persistence
* Use radio for specifying persistence type
* Don't lock nil path
* Simplify FileGuard implementation
* Test notebook persistence
* Fix typo
* Further simplify FileGuard
* Improve file listing
* Don't show parent dir when there's a basename being typed
* Add path component tests
* Initial file import/export
* Add renderer tests
* Refactor renderer
* Depend only on EarmarkParser
* Add test for export
* Add import tests
* Improve import
* Document the ExMd file format
* Rename ExMd to ExMarkdown
* Rename ExMarkdown to LiveMarkdown
* Build iodata when exporting a notebook
* Persist metadata as a single JSON object
* Move Markdown to LiveMarkdown.MarkdownHelpers
* Make LiveMarkdown private
* Always move primary heading to the top during import
* Hint the user not to use heading 1 and 2
* Return a list of messages from the import function
* Update headings warning
* Add import and export test for non-elixir snippets
* Merge markdown renderer into MarkdownHelpers
* Add import messages on AST rewrites
