Fixes for Mii struct and FRD_GetFriendKeyList

[ZeroSkill1]

This commit introduced a regression which caused users to see invalid data when accessing the FriendMii struct. This was caused by the presence of extra fields at the beginning of the struct that are not actually part of the data returned by the friends sysmodule.

The changes made here:

• Move CFLStoreData from act.h to mii.h as it turns out this struct is shared across many titles and sysmodules;
• Define FriendMii as CFLStoreData so that commands taking in FriendMii or returning structs that contain Mii data can be accessed properly.

In addition, through my own testing I have discovered that FRD_GetFriendKeyList was passing invalid static buffer descriptors, causing a crash whenever this command was used, so I have corrected this as well.