add: Indonesian translation section + Refactor code under collapsible markdown

[ranggakd]

In this PR, I did the following:

• [x] Grammar errors fixed
• [x] Added Indonesian translation repo (mine, done)
• [x] Adding refactor code optional under collapsible markdown to understand and focus more on which part of the code is bad and good at the end (done)

[ranggakd]

pardon my commits, I'm still new with PR at the moment I requested it @TomasVotruba The issue #213