Catalog: Rename the json file to reflect the id and connectors.properties content

[oscerd]

In connectors.properties we have the following:

camel-aws2-s3-source
camel-aws2-s3-sink

while in the connectors folder

camel-aws2-s3-kafka-sink-connector.json
camel-aws2-s3-kafka-source-connector.json

And inside these files the id is:

camel-aws2-s3-sink
camel-aws2-s3-source

so it probably makes sense to rename the json as something like .json, to make the catalog easier to use.

Related to #430