Improve oj-prepare command

[kmyk]

TL;DR: いまの oj-prepare は表現力が足りてないので作り直そうぜ

Description

oj-prepare is a simple script to call oj d and oj-template.
However, this is too simple and poor. We want to use more features, for example:

• More flexible directory structures
• Watch directories and run incremental build/test
• Add some hooks after downloading samples
• Add some hooks before submitting code
  • e.g. oj-bundle, linters like pylint

Possible implementations

• Use the current oj-prepare and add more features
• Use icpc-jag/rime
  • Rime is a famous contest-preparing tool. Solving problems is very similar to preparing problems (e.g. generating test cases, writing naive solutions, etc.).
  • Rime 3 seems under developing now. Rime version 3 icpc-jag/rime#71
  • nya3jp/rules_contest
• Use Bazel
  • Bazel is a modern build tool. Build tools have similar functionalities to oj-prepare (e.g. flexible directory structures, incremental build/test, etc.). In fact, it seems Rime 3 tries to use Bazel.
  • Starlark language is a nice option even if you don't use Bazel.

Other notes

• Will you try to create a pull request?
  • No. I have no time for this issue now.
• If someone make a nice replacement of oj-prepare, I'll deprecate the current one.