Catalogendpoint (#955)

* Added new cataloger interface

* Implementing catalog protocol

* Propagated to protocol and over

* First round of fixes

* S3 almost ready, need to be tested

* Going on with testing s3

* Better testing with s3

* Simplified catalog tests

* Preparing gcp tests to access a gcp instance

* Fixing initialization errors

* Removed some prints

* Gcp ready, to be tested

* Gcp working

* Aligned bucket mock to catalog method

* Switched res payload to json

* Added catalog method to all storage instances

* Added catalog method to unsupported storages

* Fixed with pool test

* Restored tests

* Fixed gcp constructor

* Implemented catalog for fs

* Removed trace

* E2e tests, fixed fs

* Fixed module name return value

* Added cataloger method to azure storage

* Added docs

* Changed pagesize parameter name

* Fixed gofmt error

* Added json tags to result. Fixed lint warning

* Removed extra line

* Changed not implemented error to http.KindNotImplemented

* Checking for inequality on results

* Lower-cased json keys

* Added cleaning of path separator

* Fixed review comments

* Fixed docs

scripts/test_e2e.sh

@@ -59,3 +59,11 @@ clearGoModCache
 # Verify that the test works against the proxy
 export GOPROXY=http://localhost:3000
 $GO_BINARY_PATH run .
+
+CATALOG_RES=$(curl localhost:3000/catalog)
+CATALOG_EXPECTED='{"modules":[{"module":"github.com/athens-artifacts/no-tags","version":"v0.0.0-20180803171426-1a540c5d67ab"}],"next":""}'
+
+if [[ "$CATALOG_RES" != "$CATALOG_EXPECTED" ]]; then
+  echo ERROR: catalog endpoint failed
+  exit 1 # terminate and indicate error
+fi