Add file/folder-exists subactions (#371)

Co-authored-by: Whipstickgostop <8366326+Whipstickgostop@users.noreply.github.com>

Author: WhazzItToYa

streamerbot/3.api/1.sub-actions/core/file-io/file-exists.md

@@ -0,0 +1,18 @@
+---
+title: File Exists
+description: Determines if a given file exists
+version: 1.0.1
+parameters:
+  - name: File to Check if Exists
+    type: File
+    required: true
+    description: Select the file to check, or enter a path
+  - name: Variable Name
+    type: Text
+    default: fileExists
+    description: The variable name to contain the result.
+variables:
+  - name: fileExists
+    type: bool
+    description: `True` if the file exists, `False` if it doesn't.
+---

streamerbot/3.api/1.sub-actions/core/file-io/folder-exists.md

@@ -0,0 +1,18 @@
+---
+title: Folder Exists
+description: Determines if a given folder exists
+version: 1.0.1
+parameters:
+  - name: Folder to Check if Exists
+    type: File
+    required: true
+    description: Select the folder to check, or enter a path
+  - name: Variable Name
+    type: Text
+    default: folderExists
+    description: The variable name to contain the result.
+variables:
+  - name: folderExists
+    type: bool
+    description: `True` if the folder exists, `False` if it doesn't.
+---