[Enforce]: Multiple fixes & improvements.

[Evanroby]

I like to sneak into code files before adding anything to my bot, found a few things worth fixing such as:

antispam.stamp() was never called so rate limiting on tos prompts did nothing
red_delete_data_for_user silently did nothing for uncached users, get_user() returns None, so I switched to user_from_id()
resetsettings was calling clear_all() instead of clear_all_globals(), accidentally wiping everyone's acceptance
tos_prompt_antispam dict grew forever, so I added a periodic clear + immediate pop on accept

also removed an unused datetime import, redundant @commands.is_owner() on set_link subcommand whose parent already restricts it, wrong docstring on AcceptView (view isn't persistent as it times out) and a type hint on reset_user

[ltzmax]

Thank you!