Implement "cloudlet uninstall" command

[agperson]

• Remove a local cloudlet from disk
• If it is installed in multiple locations, prompt for which to remove, or all
• Prompt to remove overrides file(s), if they exist
• Prompt to destroy stacks based on this cloudlet, if they exist

[agperson]

Partially implemented in 57fd554, but missing multi-location prompting, awareness of local/overrides, and stack awareness.

[agperson]

Implemented multi-location prompting in 1d36052.

[robparrott]

Danny, can you elaborate on the "overrides" file aspect?

[agperson]

Overrides, nee Local, now cloudlet sections in the config file. So, delete the section upon deletion of the last installed version of the cloudlet (i.e. don't delete if it has been installed in multiple locations and we are not uninstalling all of them).

[agperson]

Remaining functionality (stack deletion) is tracked in #98. I'm not sure there is a need to remove the scoped params on uninstall, what's the harm in keeping them around for future use?