refactor(devs-infra): restructure project + adjust astTransformers config

[ahnpnl]

Summary

• Restructure project to prepare for yarn workspace

• Let test apps install jest-preset-angular from src directory instead of root directory. This will greatly improve CI speed as well as local development. When we install this preset from root directory, yarn will start linking node_modules of root directory + node_modules of test apps themselves, which takes lots of time.

• Adjust astTransformers config for jest-preset.js since string array config is deprecated in ts-jest 26.2.0

• Adjust README.md

After this restructuring:

• Whenever we publish the package, we need to do npm pack or yarn pack in src directory instead of root directory.

• We will only pack and publish with compiled codes + package.json. Previously we publish with many other things.

Closes #439

Test plan

Green CI

Does this PR introduce a breaking change?

• Yes
• No

Other information

N.A.

[wtho]

Good Job 👍

[wtho]

Is the build folder nested inside src? I think next to each other should be better, but I might overlook something

[ahnpnl]

ya now build folder will be inside src, when we run npm pack or yarn pack in src, it will produce the same tgz file as before this PR.

[ahnpnl]

the idea is for now we produce the tgz file with the same content as before this PR. Then in the next major release, we can consider to get rid of build in the tgz file content. So the whole tgz file content will potential be:

node_modules
-- jest-preset-angular
    -- index.js
    -- jest-preset.js
    -- zone-patch.js
    -- <other_transformers>.js
    -- <other_snapshot_serializers>.js

[ahnpnl]

can we merge this ?

[wtho]

Yes! LGTM!