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/mailru/easyjson/jlexer/bytestostr.go

@@ -0,0 +1,21 @@
+// This file will only be included to the build if neither
+// easyjson_nounsafe nor appengine build tag is set. See README notes
+// for more details.
+
+//+build !easyjson_nounsafe
+//+build !appengine
+
+package jlexer
+
+import (
+	"unsafe"
+)
+
+// bytesToStr creates a string pointing at the slice to avoid copying.
+//
+// Warning: the string returned by the function should be used with care, as the whole input data
+// chunk may be either blocked from being freed by GC because of a single string or the buffer.Data
+// may be garbage-collected even when the string exists.
+func bytesToStr(data []byte) string {
+	return *(*string)(unsafe.Pointer(&data))
+}

e2e/vendor/github.com/mailru/easyjson/jlexer/bytestostr_nounsafe.go

@@ -0,0 +1,13 @@
+// This file is included to the build if any of the buildtags below
+// are defined. Refer to README notes for more details.
+
+//+build easyjson_nounsafe appengine
+
+package jlexer
+
+// bytesToStr creates a string normally from []byte
+//
+// Note that this method is roughly 1.5x slower than using the 'unsafe' method.
+func bytesToStr(data []byte) string {
+	return string(data)
+}

e2e/vendor/github.com/mailru/easyjson/jlexer/error.go

@@ -0,0 +1,15 @@
+package jlexer
+
+import "fmt"
+
+// LexerError implements the error interface and represents all possible errors that can be
+// generated during parsing the JSON data.
+type LexerError struct {
+	Reason string
+	Offset int
+	Data   string
+}
+
+func (l *LexerError) Error() string {
+	return fmt.Sprintf("parse error: %s near offset %d of '%s'", l.Reason, l.Offset, l.Data)
+}