Changed the way that modules are detected to work with Redis Enterprise

[simonprickett]

Using module list to determine whether a module is installed wasn't working with Redis Enterprise, changing it to use the command info command. Closes #73

[simonprickett]

@itamarhaber wondering if you'd mind reviewing this PR to Redis OM Python that changes use of module list to determine if JSON and/or Search are installed as this doesn't work on Redis Enterprise. Uses command info ft.search and command info json.get instead, which return [None] if the command doesn't exist. Tested on Redis Enterprise cloud and OSS Redis 6.2.6 with and without Search and JSON installed.

[itamarhaber]

Yeah, that's how the rest of us are doing it