rebase: vendor dependencies for Vault API

Uses github.com/libopenstorage/secrets to communicate with Vault. This
removes the need for maintaining our own limited Vault APIs.

By adding the new dependency, several other packages got updated in the
process. Unused indirect dependencies have been removed from go.mod.

Signed-off-by: Niels de Vos <ndevos@redhat.com>

vendor/github.com/ryanuber/go-glob/README.md

@@ -0,0 +1,29 @@
+# String globbing in golang [![Build Status](https://travis-ci.org/ryanuber/go-glob.svg)](https://travis-ci.org/ryanuber/go-glob)
+
+`go-glob` is a single-function library implementing basic string glob support.
+
+Globs are an extremely user-friendly way of supporting string matching without
+requiring knowledge of regular expressions or Go's particular regex engine. Most
+people understand that if you put a `*` character somewhere in a string, it is
+treated as a wildcard. Surprisingly, this functionality isn't found in Go's
+standard library, except for `path.Match`, which is intended to be used while
+comparing paths (not arbitrary strings), and contains specialized logic for this
+use case. A better solution might be a POSIX basic (non-ERE) regular expression
+engine for Go, which doesn't exist currently.
+
+Example
+=======
+
+```
+package main
+
+import "github.com/ryanuber/go-glob"
+
+func main() {
+    glob.Glob("*World!", "Hello, World!") // true
+    glob.Glob("Hello,*", "Hello, World!") // true
+    glob.Glob("*ello,*", "Hello, World!") // true
+    glob.Glob("World!", "Hello, World!")  // false
+    glob.Glob("/home/*", "/home/ryanuber/.bashrc") // true
+}
+```