Small changes for DeviceSelectorModa props API

[dgdavid]

Changes

Before:

  <DeviceSelectorModal                                                                                             
    disksSideEffects={<DiskNote />}
    mdRaidsSideEffects={<MdNote />}                                                                                  
    volumeGroupsSideEffects={<VgNote />}
    disksIntro="Choose a disk..."                                                                                  
    mdRaidsIntro="Choose a RAID..."                                                                                
    volumeGroupsIntro="Choose a VG..."                                                                             
    volumeGroupsEmptyTitle="No VGs"                                                                                
    newVolumeGroupLinkText="Create LVM"                                                                            
  />

After:

  <DeviceSelectorModal
    sideEffects={{ disks: <DiskNote />, mdRaids: <MdNote />, volumeGroups: <VgNote /> }}
    tabIntros={{ disks: "Choose a disk...", mdRaids: "Choose a RAID...", volumeGroups: "Choose a VG..." }}
    emptyStateTitles={{ volumeGroups: "No VGs" }}                                                                  
    newDeviceLinkTexts={{ volumeGroups: "Create LVM" }}
  />                                                                                                               

Benefits

• Type-safe: compiler enforces valid tab keys
• Cleaner: groups related config by concern
• Extensible: adding new tabs only requires updating TabKey type

[dgdavid]

@ancorgs this is the props API change I told you during the morning. Please review and merge it if you find it useful or, at least, not that harmful.

[ancorgs]

LGTM