Update content for International Candidates section

[frankieroberto]

This updates the content on the course pages which is aimed at international students, following a review with the international recruitment team.

We have:

• Re-titled the section from "International students" to "International candidates"
• Made the language confirming visa sponsorship being available less certain ("contact us to check"), as providers may not have answered the question correctly, and it may be more complicated than a simple answer
• Explained that other types of visa may be available, such as Graduate and family visas
• Added a link to the Train to teach in England if you’re a non-UK citizen guidance page
• Added a sub-section about international qualifications and getting a UK ENIC statement

💻 Preview these changes in a temporary deployment
🗂️ Trello card

Screenshots

Fee-paying, sponsorship available

Fee-paying, sponsorship not available

Salaried, sponsorship available

Salaried, sponsorship not available

Thanks to: @EmmaFrith, Laura Tennant, Mathilde Boccanera, Becky Johnes and others.

[YoniF1]

Nice! LGTM