refactor: optimize type usage (#8947)

jest.config.ts

lib/config-validator.ts

lib/config/admin.ts

lib/config/cli.spec.ts

lib/config/cli.ts

lib/config/decrypt.ts

lib/config/defaults.ts

lib/config/definitions.ts

lib/config/env.spec.ts

lib/config/env.ts

lib/config/file.ts

lib/config/index.ts

lib/config/massage.ts

lib/config/migrate-validate.ts

lib/config/migration.ts

lib/config/presets/bitbucket-server/index.ts

lib/config/presets/gitea/index.ts

lib/config/presets/github/index.ts

lib/config/presets/gitlab/index.ts

lib/config/presets/index.ts