[llvm-pdbutil] Move global state (Filters) inside LinePrinter class.

The changes described by:

https://reviews.llvm.org/D121801
https://reviews.llvm.org/D122226

Moved some llvm-pdbutil functionality to the debug PDB library.

This patch addresses one outstanding issue concerning the global
state (Filters) created in the PDB library.

- Move 'Filters' inside the 'LinePrinter' class.
- Omit 'Optional' and just pass 'PrintScope &HeaderScope' everywhere.

Reviewed By: aganea

Differential Revision: https://reviews.llvm.org/D122887