[c++] Add server settings for adjusting weapon haste cap

[CriticalXI]

I affirm:

• I understand that if I do not agree to the following points by completing the checkboxes my PR will be ignored.
• I understand I should leave resolving conversations to the LandSandBoat team so that reviewers won't miss what was said.
• I have read and understood the Contributing Guide and the Code of Conduct.
• I have tested my code and the things my code has changed since the last commit in the PR and will test after any later commits.

What does this pull request do?

• Adds a server setting to set what value to cap out weapon haste caps.

Steps to test these changes

• Set haste cap to 0.07 and give yourself all the haste buffs, see the cap is raised from 80% to 93%