rust: pci: Allocate and manage PCI interrupt vectors

rust: pci: Allocate and manage PCI interrupt vectors

Add support to PCI rust module to allocate, free and manage IRQ vectors.
Integrate with devres for managing the allocated resources.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
[ Add links in doc-comments; add missing invariant comment; re-format
  multiple safety requirements as list and fix missing backticks;
  refactor the example of alloc_irq_vectors() to compile. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>