Groups with space at the beginning or end of the name can be created with the Provisioning API

## Describe the bug
core PR https://github.com/owncloud/core/pull/39540 is improving/changing the group name validation in core.
oCIS should behave the same - there should not be any space allowed at the beginning and/or end of a group name.

## Steps to reproduce
Run the related new API tests:
```
apiProvisioningGroups-v1/addGroup.feature:158
apiProvisioningGroups-v1/addGroup.feature:166
apiProvisioningGroups-v1/addGroup.feature:174
apiProvisioningGroups-v2/addGroup.feature:154
apiProvisioningGroups-v2/addGroup.feature:162
apiProvisioningGroups-v2/addGroup.feature:170
```

## Expected behavior
Groups with space at the start or end of the name should not be allowed to be created:
" space-at-start"
"space-at-end "
" "
Those should all be prohibited group names.

## Actual behavior
Those names can be use when creating a group with the Provisioning API.

## Setup
Current ocis master.