cloudapi: use Recover middleware to handle panics

recover from panics such as out-of-bounds array access & nil
pointer access, print a stack trace and return 5xx error
instead of the service crashing and relying on Execution
framework to handle crashes

vendor/github.com/labstack/gommon/bytes/README.md

@@ -0,0 +1,29 @@
+# Bytes
+
+- Format bytes integer to human readable bytes string.
+- Parse human readable bytes string to bytes integer.
+
+## Installation
+
+```go
+go get github.com/labstack/gommon/bytes
+```
+
+## [Usage](https://github.com/labstack/gommon/blob/master/bytes/bytes_test.go)
+
+### Format
+
+```go
+println(bytes.Format(13231323))
+```
+
+`12.62MB`
+
+### Parse
+
+```go
+b, _ = Parse("2M")
+println(b)
+```
+
+`2097152`