Similar to commit 7e735035, this commit makes the order of header file
inclusion consistent for non-backend modules.

In passing, fix the case where we were using angle brackets (<>) for the
local module includes instead of quotes ("").

Author: Vignesh C
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/CALDaNm2Sznv8RR6Ex-iJO6xAdsxgWhCoETkaYX=+9DW3q0QCfA@mail.gmail.com