Motivation:

`RESPValue` exposes a fair amount of complexity on how to intialize a single instance with the various overloads.

This aims to simplify the complexity for developers by providing a single initializer and relying on `RESPValueConvertible` to handle the complexities.

In addition, the Swift complier synthesizes a lot of default conformances that `RedisKey` has manually written, which is just unnecessary code.

Modifications:

- Rename: `RESPValue.init(_:)` to `RESPValue.init(from:)`
- Change: `RESPValue.init` `String?` and `FixedWidthInteger` overloads from `public` to `internal`
- Remove: Unnecessary code for various protocol conformances for `RedisKey`

Result:

Developers should have a direct and guided way of making instances of `RESPValue`