Add HTTP PATCH support to KV (#12687)

* handle HTTP PATCH requests as logical.PatchOperation

* update go.mod, go.sum

* a nil response for logical.PatchOperation should result in 404

* respond with 415 for incorrect MIME type in PATCH Content-Type header

* add abstraction to handle PatchOperation requests

* add ACLs for patch

* Adding JSON Merge support to the API client

* add HTTP PATCH tests to check high level response logic

* add permission-based 'kv patch' tests in prep to add HTTP PATCH

* adding more 'kv patch' CLI command tests

* fix TestHandler_Patch_NotFound

* Fix TestKvPatchCommand_StdinValue

* add audit log test for HTTP PATCH

* patch CLI changes

* add patch CLI tests

* change JSONMergePatch func to accept a ctx

* fix TestKVPatchCommand_RWMethodNotExists and TestKVPatchCommand_RWMethodSucceeds to specify -method flag

* go fmt

* add a test to verify patching works by default with the root token

* add changelog entry

* get vault-plugin-secrets-kv@add-patch-support

* PR feedback

* reorder some imports; go fmt

* add doc comment for HandlePatchOperation

* add json-patch@v5.5.0 to go.mod

* remove unnecessary cancelFunc for WriteBytes

* remove default for -method

* use stable version of json-patch; go mod tidy

* more PR feedback

* temp go get vault-plugin-secrets-kv@master until official release

Co-authored-by: Josh Black <raskchanky@users.noreply.github.com>

sdk/logical/response_util.go

@@ -17,7 +17,7 @@ import (
 func RespondErrorCommon(req *Request, resp *Response, err error) (int, error) {
 	if err == nil && (resp == nil || !resp.IsError()) {
 		switch {
-		case req.Operation == ReadOperation:
+		case req.Operation == ReadOperation, req.Operation == PatchOperation:
 			if resp == nil {
 				return http.StatusNotFound, nil
 			}