redis client socket changes needed for sentinel

[sjpotter]

Description

Describe your pull request here

redoes the redis socket typing to make it more consistent and easier to use in other types. Had difficulties with typescript checking, as its now consistently uses interfaces instead of a mix of type and interfaces, seems to work better for me.

but to achieve that, had to rename one member as otherwise would have clashes.

Checklist

• Does npm test pass with this change (including linting)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?