Avoid using-directives in headers

[vkucera]

Using-directives should never appear in headers because they irreversibly pollute the global namespace wherever they are included and can lead to unexpected behaviour, such as name conflicts. See O2 CodingGuidelines.

[vkucera]

Fixed non-PWG directories

• Remove using-directives from common headers #3324

[vkucera]

• Fix namespace pollution from std and o2::constants #3423
• Fix namespace pollution from std and o2::constants AliceO2#11851

[vkucera]

• PWGHF: Avoid using-directives in headers #3617

[vkucera]

Test implemented in:

• Add O2 linter #7066