Remove `CONFIG_` prefix from KinesisConfigConstants variables

I find the static variable names verbose. I think it's clear from context that they refer to the Kinesis configuration since they are all gathered in that class.

Therefore would like to remove the CONFIG_ prefix before the release, so that we have

conf.put(KinesisConfigConstants.AWS_REGION, "")

instead of

conf.put(KinesisConfigConstants.CONFIG_AWS_REGION, "")

For longer variables it becomes even longer otherwise.

—

Some basic variable names that might be accessed frequently are also very long:

CONFIG_AWS_CREDENTIALS_PROVIDER_BASIC_SECRETKEY
CONFIG_AWS_CREDENTIALS_PROVIDER_BASIC_ACCESSKEYID

It might suffice to just have:

AWS_SECRET_KEY
AWS_ACCESS_KEY