Improve issue templates (#1686)

.github/ISSUE_TEMPLATE/report-bug.md

@@ -0,0 +1,36 @@
+---
+name: Report a bug
+about: Report a bug or a functional regression
+title: 'Ex: In DarkMode, a blank square appears in bottom right corner while scrolling'
+labels: ['type: bug']
+assignees: ''
+
+---
+
+## Bug Description
+
+A clear and concise description of what the current behavior is.
+Please also add **screenshots** of the existing application.
+
+**Example:** 
+```
+In DarkMode, when scrollbar are displayed (for example on Companies page, with enough companies in the list), we see a blank square in the bottom right corner
+[screenshot]
+```
+
+## Expected behavior
+
+A clear and concise description of what the expected behavior is.
+
+**Example:** 
+```
+The blank square should be transparent (invisible)
+```
+
+## Technical inputs
+
+**Example:** 
+```
+- We are displaying custom scrollbars that disappear when the user is not scrolling. See ScrollWrapper.
+- Probably fixable with CSS
+```