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/test.sh

@@ -13,12 +13,13 @@ TIMEOUT=$7
 COVERMODE=$8
 
 PACKAGES_COMMA=$(echo $PACKAGES | tr ' ' ',')
+export MM_SERVER_PATH=$PWD
 
 echo "Packages to test: $PACKAGES"
 echo "GOFLAGS: $GOFLAGS"
 
 find . -name 'cprofile*.out' -exec sh -c 'rm "{}"' \;
-find . -type d -name data -not -path './vendor/*' -not -path './data' | xargs rm -rf
+find . -type d -name data -not -path './data' | xargs rm -rf
 
 $GO test $GOFLAGS -run=$TESTS $TESTFLAGS -v -timeout=$TIMEOUT -covermode=$COVERMODE -coverpkg=$PACKAGES_COMMA -exec $DIR/test-xprog.sh $PACKAGES 2>&1 > >( tee output )
 EXIT_STATUS=$?