Add .js Extensions to Imports statements

[rkodev]

We need to evaluate whether to add .js extensions to import statements across all packages in this repository.

Verify the configuration of tsconfig. Depending on the options set, it can:

• Automatically add the missing .js extension or not.
• Automatically add index or not.

Additionally, define the hows and whys of this process.

[EricAtMSFT]

I noticed that the Kiota lib I generated (using V 1.27.0) there were quite a few imports statements pointing to .js files....that don't exist since the client generates .ts assets. I removed all then ".js" manually and the client built fine after that but it does seem like there's an issue here.