Change sidebar order

[tomer953]

As discussed here: #154

I implemented sorting by difficulty.

challenge-number.json contains counters for each difficulty:

{
  "total": 35,
  "🟢": 12,
  "🟠": 116,
  "🔴": 207
}

Notes

1. I chose to use 1, 101, 201 (and not 100, 200) to be consist (since "easy" starting with 1, and not from 0)
2. I first reordered manually all the items by diffulty (first commit), and test it, then moved to the generator.ts part

I found two bugs in the current implementaion (regardless to the sort order) -
a. new challanges is created with the wrong index (try to create one now, the filename will be 35-foo, when its need to be 36-foo, since 35 already taken)
b. even in dry-run mode, two files were created, this is because you used writeFile (and readFile) from fs instead of nx tree

I fixed them both.

please review and test

[tomalaforge]

Yes that's true about the bugs. I fixed them but didn't push the code 😅 But thanks for fixing it

[tomalaforge]

This is really nice and perfect. UX is so much nicer 🔥

Thanks a lot for this PR.

[tomalaforge]

@all-contributors add @tomer953 for doc,code

[allcontributors]

@tomalaforge

I've put up a pull request to add @tomer953! 🎉