Prepare repo for open sourcing

[mturoci]

A few things that in my opinion should be done before making this repo public:

• Setup a CI pipeline. Despite the fact we use company-wise Jenkins, it is most of the time busy. I would prefer to have something always ready so we can run our tests on each PR. I have found CI providers with completely free tier for public repos - e.g. Travis CI (there can be others suitable as well of course).
• Contribution / developer guide.
• Setup git hooks to run tests related to staged files on commit - enforcing at least some unit tests to run before pushing.
• Custom tslint rules to keep consistency since the codebase has a pretty specific style e.g. someVariableB for boxed vars, using const just once and separate variables with , instead of multiple lines starting with const etc.
• IDE support - common editorconfig, vs-code plugin suggestions for this project etc.

@lo5 @geomodular Let's use this issue as a starting point for a discussion.

[mturoci]

In addition to points above, since tslint is deprecated, I am going to replace it with typescript-eslint as suggested in the official docs.

[mturoci]

Other possible improvements regarding git hooks:

• Consistent commit message format (e.g. conventional commits).
• Implement git hooks for the whole repo and add support for linting staged files other than JS - (.py, .md, .go).

@lo5 @geomodular

[lo5]

Agree @mturoci - I'm fine with conventional commits as long as the [optional scope] part is not enforced.

[mturoci]

In order to enforce git hooks for each developer I use husky in combination with lint-staged for linting.

It works fine for ui part of repo since I have included it in package.json there. However, if we want to use it for the whole repo, I would have to create a package.json and corresponding node_modules in project root and set it all there.
Despite the fact I think project root should not be polluted with nodejs or any other language specific files other than configs, I could not find any other way around it.

Problem no. 2 is that for commit linting and markdown linting there exist npm packages, go has native linter as part of an SDK, but the problem is python one. As far as I discovered, python requires pip installing the linter locally. This would introduce requirements.txt in project root. @lo5 any idea as someone who has much broader python experience? Please also read the previous section.

[mturoci]

Adding .nvmrc with current LTS Node version (via @mnezh)