docs: fix reverse proxy guides (#9118)

# Which Problems Are Solved

Commands for installing compose stacks with reverse proxies don't work.

# How the Problems Are Solved

- The `docker compose up` commands are fixed by specifying all necessary
services to spin up. This is obviously not (or not with all docker
compose versions) resolved by the dependencies declarations.
- The initial postgres admin username is postgres.
- Fix postgres health check to succeed before the init job created the
DB.
- A hint tells the user to install the grpcurl binary.

# Additional Changes

- Passing `--wait` to `docker compose up` doesn't require us to sleep
for exactly three seconds.
- It looks to me like the order of the depends_on declaration for
zitadel matters, but I don't understand why. I changed it so that it's
for sure correct.
- Silenced some command outputs
- Removed the version property from all compose files to avoid the
following warning
```
WARN[0000] /tmp/caddy-example/docker-compose-base.yaml: the attribute `version` is obsolete, it will be ignored, please remove it to avoid potential confusion
```

# Additional Context

- Closes https://github.com/zitadel/zitadel/issues/9115

This is the easiest way to test the updated docs:

```bash
# Use this PR branches files:
export ZITADEL_CONFIG_FILES=https://raw.githubusercontent.com/zitadel/zitadel/refs/heads/fix-reverse-proxy-guides/docs/docs/self-hosting/manage/reverseproxy
```

The rest of the commands as described in
https://docs-git-fix-reverse-proxy-guides-zitadel.vercel.app/docs/self-hosting/manage/reverseproxy/caddy


![image](https://github.com/user-attachments/assets/949d2c2a-246a-49a2-916a-e77250771074)

e2e/config/host.docker.internal/docker-compose.yaml

@@ -1,5 +1,3 @@
-version: '3.8'
-
 services:
 
   db:

e2e/config/localhost/docker-compose.yaml

@@ -1,5 +1,3 @@
-version: '3.8'
-
 services:
   zitadel:
     user: '$UID'

e2e/docker-compose.yaml

@@ -1,5 +1,3 @@
-version: '3.8'
-
 services:
   zitadel:
     extends: