docs: updated applications URL

[hackermondev]

The URL that is shows in the docs is the old url for applications. In this pull request I updated the URL to the right url.

Please describe the changes this PR makes and why it should be merged:
The URL that is shows in the docs is the old url for applications. In this pull request I updated the URL to the right url. In the future Discord might show a 404 page for that url so everything needs to be ready and updated.

Status

• [ Yes ] Code changes have been tested against the Discord API, or there are no code changes
• [ Yes ] I know how to update typings and have done so, or typings don't need updating

Semantic versioning classification:

• [ No ] This PR changes the library's interface (methods or parameters added)
  • [ No ] This PR includes breaking changes (methods removed or renamed, parameters moved or removed)
• [ Yes ] This PR only includes non-code changes, like changes to documentation, README, etc.

[vaporoxx]

This link is present multiple times in the library and should be changed in each file, I have listed them here [deleted]

[hackermondev]

@Vaporox done