Migrate repository link in New Repository dialogue not using subdir from Base URL

[dugite-code]

• Gitea version (or commit ref): 1.15.0+dev-65-g0bb8bd819 built with GNU Make 4.3, go1.16.3 : bindata, timetzdata, sqlite, sqlite_unlock_notify
• Git version:
• Operating system: docker Linux (Debian)
• Database (use [x]):
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL)
  • No
• Log gist:

Description

Setting the base url to a subdir e.g. https://example.tld/git/ (tested in docker) then selecting create new repository it shows a link for migrations. This link points to the relative path /repo/migrate resolving to https://example.tld/repo/migrate instead of the correct https://example.tld/git/repo/migrate

Screenshots