Migrate from Flow to TypeScript

[mohoff]

Goal of this initial PR is to have a drop-in replacement for our existing @brickblock/strong-config. This means primarily that all flow-types are converted to Typescript typings. Additionally, typescript-specific project setup, CI setup, unit tests, dynamic type generation for Config object.

Donezo:

• Setup Typescript project with tsconfig.json and eslint+prettier.
• Migrate code base to Typescript
• Refactored code into more composed utils
• Generate Typescript types instead of Flowtypes for config object
• Added test. Coverage above 80%

Not in the scope of this MR:

• Make everything super nice
• Enduser-ready README, CONTRIBUTIONS, LICENSE
• line-perfect job definitions in .gitlab-ci.yml

These and more should be extracted into separate GitHub issues and addressed in future, hopepfully smaller, PRs

[chapati23]

Great, super excited to start working on this out in the open!

Before we move this PR out of WIP, i have the following requests:

• Add a little PR description on what this PR focusses on and therefore what reviewers should focus on. I assume a great chunk of the changed files are the result of bbk sync, so I'm not sure what I can ignore and where TypeScript-specific changes were introduced here
• Maybe also make explicit what's NOT in scope of this PR. E.g. if CI setup will be done in a separate PR that's totally fine (didn't see any checks in GitHub's UI, hence my impression that nothing was running)
• As this is our very first TypeScript MR of all times ever, it would be nice if you could add some quick thoughts on why you went with your chosen setup in case you deviated from any TypeScript defaults. E.g. is lib the standard build folder for TypeScript? If not, what made you chose it? Stuff like this.

[chapati23]

have to get used to this double-submission of review comments...

[chapati23]

still figuring out what useful comment to write here when submitting a review :D

[PaddyMc]

Should we add a CONTRIBUTING.md file? It may help attract open-source devs.

Reasoning
Example

Maybe not for this PR tho, wdyt?

[chapati23]

Should we add a CONTRIBUTING.md file? It may help attract open-source devs.

Reasoning
Example

Maybe not for this PR tho, wdyt?

Great idea, can you create a new ticket for this @PaddyMc ?