Add clang tidy

[regit]

This patchset adds a .clang-tidy file. It will be used by clangd to provide additional diagnostics in the code.

Some of the warnings especially the ones about using magic number are quite verbose but this may be a good idea to implement fixes to improve the situation.

Note: the forbidden functions part requires clang-20 (so compilation from git) to work

Contribution style:

• [x] I have read the contributing guide lines at https://docs.suricata.io/en/latest/devguide/contributing/contribution-process.html

Our Contribution agreements:

• [x] I have signed the Open Information Security Foundation contribution agreement at https://suricata.io/about/contribution-agreement/ (note: this is only required once)

Changes (if applicable):

• [x] I have updated the User Guide (in doc/userguide/) to reflect the changes made
• [x] I have updated the JSON schema (in etc/schema.json) to reflect all logging changes (including schema descriptions)
• [x] I have created a ticket at https://redmine.openinfosecfoundation.org/projects/suricata/issues

Link to ticket: https://redmine.openinfosecfoundation.org/issues/3837

Describe changes:

• Add clang-tidy file
• Fix a thread safety warning to be able to use concurrency checks