Add warning to datadirectory parameter

[SystemKeeper]

• FileIDs should not change when datadirectory is moved groupfolders#2719
• Allow moving the datadirectory to another location server#42581

🖼️ Screenshots

[SystemKeeper]

/backport to stable28

[SystemKeeper]

/backport to stable27

[SystemKeeper]

/backport to stable26

[backportbot-nextcloud]

The backport to stable27 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable27
git pull origin stable27

# Create the new backport branch
git checkout -b fix/foo-stable27

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable27

Error: Unknown error

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[SystemKeeper]

/backport to stable27

[backportbot-nextcloud]

The backport to stable27 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable27
git pull origin stable27

# Create the new backport branch
git checkout -b fix/foo-stable27

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable27

Error: Unknown error

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport