MM-43753: Module workspaces (#20113)

* MM-43753: Module workspaces

Move to module workspaces

We make the following changes:
- Remove the vendor directory.
- Dynamically create the go.work file if it doesn't exist.
- Set the MM_SERVER_PATH for enterprise tests.

https://mattermost.atlassian.net/browse/MM-43753

```release-note
NONE
```

* Fix missing reference to MM_SERVER_PATH

```release-note
NONE
```

* Update test to add another nested dir

```release-note
NONE
```

* Have separate script to create go.work file

```release-note
NONE
```

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

scripts/prereq-check.sh

@@ -35,7 +35,7 @@ echo "Checking prerequisites"
 
 REQUIREDNODEVERSION=16.0.0
 REQUIREDNPMVERSION=7.10.0
-REQUIREDGOVERSION=1.14.0
+REQUIREDGOVERSION=1.18.0
 REQUIREDDOCKERVERSION=17.0
 
 NODEVERSION=$(sed 's/v//' <<< $(node -v))