Enable poetry non-package mode (#31282)

[Poetry
1.8.0](https://github.com/python-poetry/poetry/releases/tag/1.8.0) added
support for [non-package
mode](https://python-poetry.org/docs/basic-usage/#operating-modes), e.g.
projects that are not python packages themselves like we are. Make use
of that and remove the previous workaround via `--no-root`.

(cherry picked from commit 15debbbe4eb94c1855a0178e379b7e3d19bd07ad)

Conflicts:
	Makefile
	pyproject.toml
	trivial context conflict

Makefile

@@ -893,7 +893,7 @@ node_modules: package-lock.json
 	@touch node_modules
 
 .venv: poetry.lock
-	poetry install --no-root
+	poetry install
 	@touch .venv
 
 .PHONY: fomantic

pyproject.toml

@@ -1,8 +1,5 @@
 [tool.poetry]
-name = "forgejo"
-version = "0.0.0"
-description = ""
-authors = []
+package-mode = false
 
 [tool.poetry.dependencies]
 python = "^3.10"