build: move e2e dependencies into e2e/go.mod

Several packages are only used while running the e2e suite. These
packages are less important to update, as the they can not influence the
final executable that is part of the Ceph-CSI container-image.

By moving these dependencies out of the main Ceph-CSI go.mod, it is
easier to identify if a reported CVE affects Ceph-CSI, or only the
testing (like most of the Kubernetes CVEs).

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

e2e/vendor/github.com/google/gofuzz/README.md

@@ -0,0 +1,89 @@
+gofuzz
+======
+
+gofuzz is a library for populating go objects with random values.
+
+[![GoDoc](https://godoc.org/github.com/google/gofuzz?status.svg)](https://godoc.org/github.com/google/gofuzz)
+[![Travis](https://travis-ci.org/google/gofuzz.svg?branch=master)](https://travis-ci.org/google/gofuzz)
+
+This is useful for testing:
+
+* Do your project's objects really serialize/unserialize correctly in all cases?
+* Is there an incorrectly formatted object that will cause your project to panic?
+
+Import with ```import "github.com/google/gofuzz"```
+
+You can use it on single variables:
+```go
+f := fuzz.New()
+var myInt int
+f.Fuzz(&myInt) // myInt gets a random value.
+```
+
+You can use it on maps:
+```go
+f := fuzz.New().NilChance(0).NumElements(1, 1)
+var myMap map[ComplexKeyType]string
+f.Fuzz(&myMap) // myMap will have exactly one element.
+```
+
+Customize the chance of getting a nil pointer:
+```go
+f := fuzz.New().NilChance(.5)
+var fancyStruct struct {
+  A, B, C, D *string
+}
+f.Fuzz(&fancyStruct) // About half the pointers should be set.
+```
+
+You can even customize the randomization completely if needed:
+```go
+type MyEnum string
+const (
+        A MyEnum = "A"
+        B MyEnum = "B"
+)
+type MyInfo struct {
+        Type MyEnum
+        AInfo *string
+        BInfo *string
+}
+
+f := fuzz.New().NilChance(0).Funcs(
+        func(e *MyInfo, c fuzz.Continue) {
+                switch c.Intn(2) {
+                case 0:
+                        e.Type = A
+                        c.Fuzz(&e.AInfo)
+                case 1:
+                        e.Type = B
+                        c.Fuzz(&e.BInfo)
+                }
+        },
+)
+
+var myObject MyInfo
+f.Fuzz(&myObject) // Type will correspond to whether A or B info is set.
+```
+
+See more examples in ```example_test.go```.
+
+You can use this library for easier [go-fuzz](https://github.com/dvyukov/go-fuzz)ing.
+go-fuzz provides the user a byte-slice, which should be converted to different inputs
+for the tested function. This library can help convert the byte slice. Consider for
+example a fuzz test for a the function `mypackage.MyFunc` that takes an int arguments:
+```go
+// +build gofuzz
+package mypackage
+
+import fuzz "github.com/google/gofuzz"
+
+func Fuzz(data []byte) int {
+        var i int
+        fuzz.NewFromGoFuzz(data).Fuzz(&i)
+        MyFunc(i)
+        return 0
+}
+```
+
+Happy testing!