Simplify building in FIPS mode

What does this MR do?

Currently, to build in FIPS mode, we need to run gitlab-pages-fips which was introduced in !716 (merged) .

Based on gitaly!4482 (merged) , this MR intends to make building in FIPS mode a compile time flag. Having the same make target (make gitlab-pages) also helps us utilize existing toolchains without any significant modifications(e.g. CNG images).

I have also made changes to the print statements based on comments in &7779 (comment 915174822)

TODO

• I added the Changelog trailer (e.g. Changelog: added) to the commits that need to be included in the changelog
• I added unit tests or they are not required
• I added acceptance tests or they are not required
• I added documentation (or it's not required)
• I followed code review guidelines
• I followed Go Style guidelines