Signed-off-by: Tomas Tomecek <[email protected]>

so we can store ports, hosts, paths in one place and just reference it

also simplifies the Containerfile

there are no models being downloaded anymore, you need to supply them
using $MODELS_PATH - this directory is bindmounted inside the llama-cpp
container

Signed-off-by: Tomas Tomecek <[email protected]>
Co-authored-by: Jiri Podivin <[email protected]>
Co-authored-by: Jiri Konecny <[email protected]>

1. align port numbers b/w code, composefile and .env
2. require PORT env vars to be nonempty
3. containerfile→build: specify containerfile path
4. fixup interpolation within .env

address review comments from @jpodivin

Signed-off-by: Tomas Tomecek <[email protected]>

so we don't interpolate inside .env which doesn't work correctly on all
compose implmentations:

```
[server]    | requests.exceptions.ConnectionError:
HTTPConnectionPool(host='$%7bllama_cpp_host%7d', port=8000): Max retries
exceeded with url: /v1/completions (Caused by
NewConnectionError('<urllib3.connection.HTTPConnection object at
0x7ff685f4bad0>: Failed to establish a new connection: [Errno -2] Name
or service not known'))
```