[Solved] 20183.b3 - Missing package manager

After i updated project from 2018.2.9 to 2018.3.b3

1. Compiler errors in packages.
2. Look for package manager to update/remove the packages
3. No package manager anywhere
4. Ok manually remove the offending package (post, srpcore, hdrp)
5. Now im getting compiler errors because my project is refering to those packages.

As you can see its impossible to fix this project because your package manager is a package itself. When i was tinkering with code generation years ago i stumbled upon this issue when you generate something and its broken, throws compiler error, or breaks something, you are stuck as the code generator CANT work anymore as compillation is broken. This is the same exact issue, because the package manager is relying on compillation itself, if the project was broken for any reason it cant compile and thus you are stuck.

UPD:

I created new project, downloaded the updated packages there and copied them over to my project. Unity is incapable of recognizing them, even tho all the files are there ready to be compiled.

SOLUTION:
0. Delete packages from your project
1. Create new project
2. Download all the updated packages
3. Copy their cache folders to your project
4. Copy Packages/manifest to your project