Remove internal AWS SDK implementation

[smallhive]

Closes #1029

[evgeniiz321]

@smallhive @roman-khimov if try to add s3 gw from this PR to nexus, it fails like this:

error	api/user_auth.go:39	failed to pass authentication	{"error": "SignatureDoesNotMatch: 403 => The request signature we calculated does not match the signature you provided. Check your key and signing method."}
info	api/router.go:177	call method	{"host": "nexus-bucket-v3.localhost:33057", "request_id": "30deb4e3-35a0-4ebd-8ccf-7b36c0124766", "method": "GetBucketACL", "bucket": "nexus-bucket-v3", "object": ""}
error	api/user_auth.go:39	failed to pass authentication	{"error": "SignatureDoesNotMatch: 403 => The request signature we calculated does not match the signature you provided. Check your key and signing method."}
info	api/router.go:177	call method	{"host": "nexus-bucket-v3.localhost:33057", "request_id": "9b1e449f-cad4-4b69-a68a-33ce814471db", "method": "GetBucketACL", "bucket": "nexus-bucket-v3", "object": ""}
error	api/user_auth.go:39	failed to pass authentication	{"error": "SignatureDoesNotMatch: 403 => The request signature we calculated does not match the signature you provided. Check your key and signing method."}
info	api/router.go:177	call method	{"host": "nexus-bucket-v3.localhost:33057", "request_id": "0ce0f1ae-eaaf-4a3f-bad9-8ff2d042d9c0", "method": "GetBucketACL", "bucket": "nexus-bucket-v3", "object": ""}
error	api/user_auth.go:39	failed to pass authentication	{"error": "SignatureDoesNotMatch: 403 => The request signature we calculated does not match the signature you provided. Check your key and signing method."}
info	api/router.go:177	call method	{"host": "nexus-bucket-v3.localhost:33057", "request_id": "d5a395cf-4a3d-4eab-b34f-b0d579e08b9e", "method": "GetBucketACL", "bucket": "nexus-bucket-v3", "object": ""}
error	api/user_auth.go:39	failed to pass authentication	{"error": "SignatureDoesNotMatch: 403 => The request signature we calculated does not match the signature you provided. Check your key and signing method."}

if use s3 gw from master (same parameters in nexus), it fails like this:

info    api/router.go:182   call method {"status": 200, "host": "nexus-bucket-v2.localhost:53689", "request_id": "a9d203e5-c3bc-4d10-b422-cb0d7843c7c9", "method": "CreateBucket", "bucket": "nexus-bucket-v2", "object": "", "description": "OK"}
error   handler/util.go:34  call method {"status": 501, "request_id": "d45cd4a9-b989-4f33-b9c8-b5c86547d870", "method": "PutBucketLifecycle", "bucket": "nexus-bucket-v2", "object": "", "description": "not implemented", "error": "NotImplemented: 501 => A header you provided implies functionality that is not implemented"}

So, it doesn't work in both cases, but errors are different.

To reproduce:

1. Run nexus (by default it runs on 8081)

docker run -d --network host --name nexus -v nexus-data:/nexus-data -e INSTALL4J_ADD_VM_PARAMS="-Dcom.amazonaws.sdk.disableCertChecking=true" sonatype/nexus3

2. Login to UI as admin (password will be here docker exec -it nexus cat /nexus-data/admin.password )
3. Go to Administration -> Repository -> Blob Stores -> Create Blob Store
4. Specify all required s3 params and click Save.

[smallhive]

This problem with the signature

error	api/user_auth.go:39	failed to pass authentication	{"error": "SignatureDoesNotMatch: 403 => The request signature we calculated does not match the signature you provided. Check your key and signing method."}

is fixed with proper configuration

Administration -> Repository -> Blob Stores -> Create Blob Store -> Advanced Connection Settings (Optional) -> Signature Version -> AWSS3V4SignerType

Then, the problem with PutBucketLifecycle:

error   handler/util.go:34  call method {"status": 501, "request_id": "d45cd4a9-b989-4f33-b9c8-b5c86547d870", "method": "PutBucketLifecycle", "bucket": "nexus-bucket-v2", "object": "", "description": "not implemented", "error": "NotImplemented: 501 => A header you provided implies functionality that is not implemented"}

Is fixed with

Administration -> Repository -> Blob Stores -> Create Blob Store -> Expiration Days -> -1

Then, the problem with GetBucketLifecycle:

Here I hacked the response from not implemented to NoSuchLifecycleConfiguration. It is enough to go through this step.

And here is the last stop sign: Etag. The Nexus uses MD5; we use sha256.

An error occurred saving data. ValidationErrorXO{id='*', message='Unable to verify integrity of data upload. Client calculated content hash (contentMD5: bOJCN+GHNw4hyUURykPbWA== in base 64) didn't match hash (etag: 564f5f204e99644ee6f532accd524086c02dcf9346a2470eb0bd177fbcd25d19 in hex) calculated by Amazon S3. You may need to delete the data stored in Amazon S3. (metadata.contentMD5: null, md5DigestStream: com.amazonaws.services.s3.internal.MD5DigestCalculatingInputStream@7fdde751, bucketName: bb2, key: metadata.properties)'}

I failed to find how to configure this moment in Nexus. According to the AWS docs, md5 is a valid behaviour. In the S3 gate, we can't change sha256 to md5 as well

[roman-khimov]

AWSS3V4SignerType is the key to me here. If it works, we're fine with this change. Other issues are... other issues.