[V3] Ignore .idea/ directory entirely (#1754)

* [V3] Ignore .idea folder entirely

Since we're not including anything from it currently, so there's no reason not to ignore it.

* Ignore IDEA project files

.gitignore

@@ -1,6 +1,3 @@
-# Trivia list repo injection
-redbot/trivia/
-
 *.json
 *.exe
 *.dll
@@ -11,30 +8,7 @@ redbot/trivia/
 # Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
 
 # User-specific stuff:
-.idea/**/workspace.xml
-.idea/**/tasks.xml
-.idea/dictionaries
-
-# Sensitive or high-churn files:
-.idea/**/dataSources/
-.idea/**/dataSources.ids
-.idea/**/dataSources.xml
-.idea/**/dataSources.local.xml
-.idea/**/sqlDataSources.xml
-.idea/**/dynamic.xml
-.idea/**/uiDesigner.xml
-
-# Gradle:
-.idea/**/gradle.xml
-.idea/**/libraries
-
-# CMake
-cmake-build-debug/
-
-# Mongo Explorer plugin:
-.idea/**/mongoSettings.xml
-
-## File-based project format:
+.idea/
 *.iws
 
 ## Plugin-specific files: