GSoC 2024 - Refine google style guide implementation

[Mauryan Kansara]

Friday, 21st June report:

Migrating all the sections to follow chapter wise testing, some of the PRs which I sent regarding this last week:

• https://github.com/checkstyle/checkstyle/pull/15088
  
• https://github.com/checkstyle/checkstyle/pull/15031
  
• https://github.com/checkstyle/checkstyle/pull/15051
  
• https://github.com/checkstyle/checkstyle/pull/15050
  
• https://github.com/checkstyle/checkstyle/pull/15030

Working on a new method "verifyWithWholeConfig()" to check input file against whole google config:

https://github.com/checkstyle/checkstyle/pull/15028

Changed the severity property of google_checks.xml to be dynamic and updated docs regarding it:

https://github.com/checkstyle/checkstyle/pull/15072