feat: add loadingMessage() to show different loadingMsg

[Rash419]

• Resolves: #
• Target version: main

Summary

Basically when using indirection it might happen that there cluster is scaling and there is request to open the document
COOL will retry after a interval to get the new routeToken but until then we update the user with the loading message that "Cluster is scaling" or something even better
corresponding COOL pr: CollaboraOnline/online#7683

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Documentation (manuals or wiki) has been updated or is not required

[juliusknorr]

I pushed some changes in also include handling of CollaboraOnline/online@d4918c7 so this also includes what is needed for #3217

[juliusknorr]

/backport to stable28

[juliusknorr]

/backport to stable27

[backportbot-nextcloud]

The backport to stable28 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable28
git pull origin stable28

# Create the new backport branch
git checkout -b fix/foo-stable28

# 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-stable28

Error: Unknown error

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

[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