Simplify local development

[SarvarD]

This PR is intended to make it easier to iterate on the TimeClock application by making local development easier.

I spent some time trying to get the app up and running on a relatively modern machine, and struggled to install all the dependencies (Python 3.6 with compatible pip versions, etc), and thought dockerizing the app (and database) would make getting up and running much easier for anyone who wants to make contributions in the future.

If this PR is approved, I'd like to follow-up with some further contributions to the app (which I contributed to during an internship and consultancy a few years ago):

• Add unit tests
• Upgrade to a more recent version of Python (it currently uses Python 3.6, which reached end-of-life in 2021)
• Make debugging easier by adding instructions on how to connect a debugger to the Docker container (looks like this should be doable through VSCode/Neovim/etc looking at some of the work others have done)
• Anything else that the team thinks might be valuable

I'm aware that the README says the team isn't looking for contributions, but I thought it was cool that this app was still being used so many years after it was developed, and I wanted to help out with its maintenance if I could - of course, if this isn't valuable to the team, feel free to reject this PR!

@johnyu95, looks like you've contributed in the past and reviewed some PRs, hoping you see this :)

[johnyu95]

Hi @SarvarD, nice to hear from you. Thanks for the contribution, we've been meaning to dockerize timeclock for some time so this definitely helps. Will test it out when I get a chance.