Substitute variables in path names of template repos too (#25294)

### Summary

Extend the template variable substitution to replace file paths. This
can be helpful for setting up log files & directories that should match
the repository name.

### PR Changes

 - Move files matching glob pattern when setting up repos from template
- For security, added ~escaping~ sanitization for cross-platform support
and to prevent directory traversal (thanks @silverwind for the
reference)
 - Added unit testing for escaping function 
- Fixed the integration tests for repo template generation by passing
the repo_template_id
- Updated the integration testfiles to add some variable substitution &
assert the outputs

I had to fix the existing repo template integration test and extend it
to add a check for variable substitutions.

Example:

![image](https://github.com/go-gitea/gitea/assets/12700993/621feb09-0ef3-460e-afa8-da74cd84fa4e)

modules/repository/generate_test.go

@@ -54,3 +54,14 @@ func TestGiteaTemplate(t *testing.T) {
 		})
 	}
 }
+
+func TestFileNameSanitize(t *testing.T) {
+	assert.Equal(t, "test_CON", fileNameSanitize("test_CON"))
+	assert.Equal(t, "test CON", fileNameSanitize("test CON "))
+	assert.Equal(t, "__traverse__", fileNameSanitize("../traverse/.."))
+	assert.Equal(t, "http___localhost_3003_user_test.git", fileNameSanitize("http://localhost:3003/user/test.git"))
+	assert.Equal(t, "_", fileNameSanitize("CON"))
+	assert.Equal(t, "_", fileNameSanitize("con"))
+	assert.Equal(t, "_", fileNameSanitize("\u0000"))
+	assert.Equal(t, "目标", fileNameSanitize("目标"))
+}