Duplicated Code for ADO PAT Generation

[Stuart-Wilcox]

Describe the bug

The code for creating an ADO PAT appears to be duplicated between two places in different packages. This makes is confusing for new people to make contributions, and is also just a poor design.

To Reproduce
See packages/node-azureauth/src/pat.ts and packages/ado-npm-auth/src/azureauth/ado.ts

Expected behavior
One file should have most of this code and then it gets imported in other places

Screenshots
Example these types

Additional context
This likely happened as an oversight when we migrated the code