feat: File Preview panel (#39)

* feat: update display preview panel

* chore: update package

* test: update unit testing

* test: update test

* test: update unit testing

* feat: update preview display to use custom renderer

* chore: use worker for react-pdf

* test: update unit testing

* chore: update requested change

* chore: update gitignore for sample files

* fix: hard-code filetype mappings

* fix: make integration test work again

* chore: update tests

* feat: add FileInfo to preview cards

Co-authored-by: Leangseu Kim <lkim@edx.org>

.gitignore

@@ -5,6 +5,7 @@ npm-debug.log
 coverage
 
 dist/
+public/samples/
 
 ### pyenv ###
 .python-version