Single-line installer is not looking for already exsisting instals

[matmair]

Please verify that this bug has NOT been raised before.

• [X] I checked and didn't find a similar issue

Describe the bug*

The installer is just installing sources and the package - not checking if there is already a config (that might be missing mandatory new keys)

Steps to Reproduce

1. Have an old instal (0.9.0 or similar)
2. Install a current version (0.14.0 or similar)
3. Have an install missing BACKUP_DIR and SITE_URL config keys, making the install more or less unusable
4. Get Errors during the install because of the already existing env

Expected behaviour

Just working

Deployment Method

• [ ] Docker
• [ ] Bare metal

Version Information

0.14.0

Please verify if you can reproduce this bug on the demo site.

• [ ] I can reproduce this bug on the demo site.

Relevant log output

No response