Provide defaults for config and keyfile

[sascha-andres]

Default for config: ~/.grapes.yml Default for key: ~/.ssh/id_rsa

[sascha-andres]

@yaronsumel I added default values for config and key as best guesses

[yaronsumel]

@sascha-andres Thanks for the contribution..

Two things that missing:

• Change the options description at:

  1. https://github.com/sascha-andres/grapes/blob/0a7197f9c5c635e80b1882d1d9d689da789f9ce8/input.go#L33
  2. https://github.com/sascha-andres/grapes/blob/0a7197f9c5c635e80b1882d1d9d689da789f9ce8/input.go#L34

• Cover that changes with small test (input_test.go)

[yaronsumel]

great work .. merged