Drop dependency on python-gnupg

According to the git log, this dependency was added for Foreman deployments.
However, we shouldn't add dependencies that are only required for DevOps
in the requirements of the package itself, since it's perfectly possible
to deploy the server using other means as well.

Supersedes #6

Author: ldionne

pyproject.toml

@@ -37,7 +37,6 @@ dependencies = [
     "Flask>=3.1.0",
     "Jinja2>=3.1.0",
     "MarkupSafe>=3.0.0",
-    "python-gnupg>=0.3.7",
     "PyYAML>=6.0.0",
     "requests",
     "SQLAlchemy==1.3.24",

requirements.client.txt

@@ -9,7 +9,6 @@ Flask==3.1.2
 itsdangerous==2.2.0
 Jinja2==3.1.6
 MarkupSafe==3.0.3
-python-gnupg==0.3.7
 pytz==2016.10
 SQLAlchemy==1.3.24
 Werkzeug==3.1.3