ruby: Introduce new RqlConnectionError

RqlRuntimeError has too large of a scope and it
is not possible to easily determine which of these
instances are retryable errors.

RqlConnectionError is to be used for retryable connection
and server errors.
python: Introduce new RqlConnectionError

RqlRuntimeError has too large of a scope and it
is not possible to easily determine which of these
instances are retryable errors.

RqlConnectionError is to be used for retryable connection
and server errors.
javascript: Introduce new RqlConnectionError

RqlRuntimeError has too large of a scope and it
is not possible to easily determine which of these
instances are retryable errors.

RqlConnectionError is to be used for retryable connection
and server errors.