Private key uploading

[AnthonyAstige]

Add a textarea for the user to add their private key

1. Add explanation: This is helpful for committing to git quickly
2. Store in localstorage only (not to database)
   1. Note this in the UI
3. Await server instantiation (Related: Delay server ready #11)
   1. Upload the private key to the server under ~/.ssh/id_rsa
      1. Note this in the UI
   2. Set file permissions as needed on ~/.ssh/id_rsa

Related (When done, check if anything there is needed)

https://trello.com/c/xCNaJHsz/8-setting-keys