Make CTA Button Links and Labels Dynamic

[zorexsalvo]

Currently, the CTA button links and labels are hardcoded. We need to make them dynamic so they can be updated easily.

Current Static Links:

• sponsor_link
• call_for_volunteers_link
• buy_tickets_link

Expected Behavior:

Allow these links and labels to be configured dynamically, either through environment variables, a settings file, or an admin panel.
Ensure that buttons do not appear if the corresponding link is empty or not set.