Removing copy&paste code, part 2

Removing copy&paste code, part 2

[Issue#] N/A
[Bug/Feature] Duplicated code
[Cause] Copy&Paste
[Solution] Extract common code, generalise it
[Verification] Build this and all dependent packages, install them accordingly and run all tests

Changes:
- In modules/db/include/dpl/db/orm.h - replaced class-local BindVisitor helper
  classes with a file-wide class.
- NamedInputPipe - code was virtually identical to FileInput, so now
  NamedInputPipe inherits after FileInput.
- Removed some code that has been commented out for most part of the year

Change-Id: I67dba22a6341bf38db198bbc31c1425ce8a41a9f