Review feedback

* Close the SFTP session
* Improve documentation
* Parameterize inputs
* Make the balances endopint URL configurable
* Add upload failure logging
* Expand some testing

Author: ConsoleCatzirl

.pre-commit-config.yaml

@@ -2,7 +2,7 @@ ci:
   autoupdate_schedule: monthly
 repos:
 -   repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v5.0.0
+    rev: v6.0.0
     hooks:
     # On Windows, git will convert all CRLF to LF, but only after all hooks are done executing.
     # yamllint will fail before git has a chance to convert line endings, so line endings must be explicitly converted before yamllint
@@ -17,7 +17,7 @@ repos:
     hooks:
     -   id: yamllint
 -   repo: https://github.com/awslabs/cfn-python-lint
-    rev: v1.38.0
+    rev: v1.38.2
     hooks:
     -   id: cfn-python-lint
         files: template\.(json|yml|yaml)$