Add `/proc/modules` support

[Dentrax]

Signed-off-by: Furkan [email protected]

I have some use-cases for this implementation:

• want to parse my /proc/interrupts file using procfs package (with go:linkname)
• move module parsing logic from node-problem-detector to here

All tests passes.

Fixes #478

[rexagod]

@Dentrax Just a nit, but can you add Fixes #478 to the description so that the original issue is closed when this gets in?