Related to 0241c71a4c

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3270#issuecomment-2143782962

With this change, it should be possible for people to adjust the Docker
dependency from `docker.service` to something else (e.g. `pkg-ContainerManager-dockerd.service`),
or to completely eliminate it by setting `devture_systemd_docker_base_docker_service_name` to an empty string.

This makes it easier for people to use the playbook against a Synology DSM server.

The new version is very broken. It has at least 2 issues.

The first one is:

```
Error: maxPromptTokens + max_tokens (3097 + 1024 = 4121) must be less than or equal to maxContextTokens (4097)
    at ChatGPTClient.setOptions (file:///usr/src/app/node_modules/@waylaidwanderer/chatgpt-api/src/ChatGPTClient.js:72:19)
    at new ChatGPTClient (file:///usr/src/app/node_modules/@waylaidwanderer/chatgpt-api/src/ChatGPTClient.js:23:14)
    at main (file:///usr/src/app/dist/index.js:62:21)
    at file:///usr/src/app/dist/index.js:94:1
    at ModuleJob.run (node:internal/modules/esm/module_job:218:25)
    at async ModuleLoader.import (node:internal/modules/esm/loader:329:24)
    at async loadESM (node:internal/process/esm_loader:28:7)
    at async handleMainPromise (node:internal/modules/run_main:113:12)
```

Likely related to:

- https://github.com/matrixgpt/matrix-chatgpt-bot/issues/246
- https://github.com/matrixgpt/matrix-chatgpt-bot/pull/248

It can be tweaked around by overriding some default environment
variables (`roles/custom/matrix-bot-chatgpt/templates/env.j2`) in order to tweak them:

```
CHATGPT_MAX_CONTEXT_TOKENS=4097
CHATGPT_MAX_PROMPT_TOKENS=2500
```

This leads us to another issue:

```
node:internal/process/promises:289
            triggerUncaughtException(err, true /* fromPromise */);
            ^
[Error: Failed to deserialize or serialize a JSON value missing field `version` at line 1 column 6704] {
  code: 'GenericFailure'
}
Node.js v20.11.1
error Command failed with exit code 1.
```

... whatever that means.

This is still very far from usable.

Various bridges and bots are still talking to
`matrix-nginx-proxy` instead of the new `matrix-homeserver-proxy` role.
These services need to be reworked. While reworking them,
various cleanups are being done as well as adding Traefik-labels to
those that need them.

update matrix_bot_chatgpt_version to 3.1.0

It wasn't used at all. It doesn't seem like there's a way to control
the log level, judging by:
- 8f9eea4114/.env.example
- 8f9eea4114/src/env.ts

OpenAI changed the model a month ago and broke the bot.
This bump fixes it and adds the default model.

matrix_bot_chatgpt_context=thread

Add support for OPENAI_PRO for ChatGPT pro subscriptions.

Co-Authored-By: Slavi Pantaleev <slavi@devture.com>