Catalog endpoint support for mongo (#985)

* 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

* Add catalog endpoint for mongo

* Add omitempty to ID

* Fix catalog tests

* update for next token

* fix e2e

* Make query readable

* Fix language and e2e script

* remove new line

scripts/test_e2e.sh

@@ -61,7 +61,7 @@ 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":""}'
+CATALOG_EXPECTED='{"modules":[{"module":"github.com/athens-artifacts/no-tags","version":"v0.0.0-20180803171426-1a540c5d67ab"}]}'
 
 if [[ "$CATALOG_RES" != "$CATALOG_EXPECTED" ]]; then
   echo ERROR: catalog endpoint failed