Avoid overhead with fprintf related functions

Based on work in [1].
According to https://cplusplus.com/reference/cstdio/fprintf/
The use of fprintf is related to the need to generate a string based on a
format, which should be different from "%s".
Since fprintf has overhead when parsing the "format" parameter, plus all
the trouble of checking the va_arg parameters.
I think this is one of the low fruits available and easy to reap.
By replacing fprintf with its equivalents, fputs and fputc,
we avoid overhead and increase security [2] and [3].

The downside is a huge big churm, which unfortunately will occur.
But, IHMO, I think the advantages are worth it.
Note that behavior remains the same, since fputs and fputc do not change
the expected behavior of fprintf.

A small performance gain is expected, mainly for the client, since there
are several occurrences in some critical places, such as
(usr/src/fe_utils/print.c).

Patch attached.
This pass check-world.

regards,
Ranier Vilela

[1]
https://www.postgresql.org/message-id/CAApHDvp2THseLvCc%2BTcYFBC7FKHpHTs1JyYmd2JghtOVhb5WGA%40mail.gmail.com
[2]
https://stackoverflow.com/questions/20837989/fprintf-stack-buffer-overflow
[3]
https://bufferoverflows.net/format-string-vulnerability-what-when-and-how/