Describe the bug

The gollum wiki https://github.com/gollum/gollum/wiki says that

Using the --template-page option, you can also use _Template file that will be used as the template for creating new pages. You can have different _Template files in different directories.

However, only the /_Template file in the root directory is checked when using --template-page

To Reproduce

1. Create file Foo/_Template and commit to git
2. Run gollum with --template-page
3. Make a new page under Foo/

Expected behavior
The content of Foo/_Template should be the raw content of a new page under Foo/
This template should be able to exist and be different from other directories.

Environment Info
Gollum 5.1.2
Running on: x86_64-linux with Ruby version 2.7.2
Using:
rugged 0.99.0
gollum-rugged_adapter 1.0
gollum-lib 5.0.6
Markdown rendering gem: kramdown
Other renderering gems:
none