Restructure Project

[tooolbox]

Two suggestions:

1. Use one of the (many, many) binary packing tools to include the assets in the binary.
2. Move main.go to the root directory so that you can easily do GO111MODULE=on go get github.com/evildecay/etcdkeeper

(I'm a little more comfortable building from source that downloading a binary release, and building from source is so easy with Go.)

Thanks!

[evildecay]

Thank you very much for your suggestions. I haven't maintained the project for a long time. I have some time recently. Since it is done in my spare time, it is not so fast. I will consider these issues to improve them.