Create Micro-package to Flatten/Format `user_agent` data for `ATM`

`while` reading the code: https://github.com/elixir-inspector/ua_inspector/blob/master/lib/ua_inspector.ex
and tests: https://github.com/elixir-inspector/ua_inspector/blob/master/test/ua_inspector/database/init_test.exs

I decided to create a _thin_ wrapper that flattens the `user_agent` data into the format that we need.

Spoiled for choice on package names:

https://hex.pm/packages/ua

https://hex.pm/packages/user_agent

# Todo

+ [ ] Create `ua` package following our usual template 🆕
+ [ ] Flatten/format the data we need and return as `Map` 🧑‍💻
+ [ ] Write _extensive_ tests using available `user_agent` data
+ [ ] Publish `ua` package to `Hex.pm` 📦
+ [ ] Use `ua` in `ATM` :shipit:

P.S: Sponsoring https://github.com/mneudert for as long as we use the fine work he has done. `#first`

Just a way to say "thanks" for the `code`. 🙏