makedeb: Move control file processing into a module

Signed-off-by: Euan Harris <euan.harris@citrix.com>
makedeb: Move specFromFile to rpmextra

Signed-off-by: Euan Harris <euan.harris@citrix.com>
makedeb: Move changelog function into its own module

Signed-off-by: Euan Harris <euan.harris@citrix.com>
makedeb: Move miscellaneous Debian packaging functions out into a module

Signed-off-by: Euan Harris <euan.harris@citrix.com>
makedeb: Fix most Pylint warnings

Signed-off-by: Euan Harris <euan.harris@citrix.com>