docs: prepare ocis migration guide from 4 to 5

[micbar]

Fixes: #736

@kulmann @butonic we still need to

• add the theme migration and
• the deprecations.

Backport to 5.0

[butonic]

I was thinking about TTL config changes that got fixed with owncloud/ocis@8e613bb

But the config var was already introduced in v4, so no change necessary

[butonic]

Another inconsistency is STORAGE_USERS_FILEMETADATA_CACHE_STORE vs STORAGE_SYSTEM_CACHE_STORE both are used to configure the filemetadata cache of storage-users / storage-system ... 😞

STORAGE_SYSTEM_CACHE_STORE should be STORAGE_SYSTEM_FILEMETADATA_CACHE_STORE

[mmattel]

I have updated and cleaned up the content.
It is also pushed to staging to see how it is finally rendered.

[micbar]

Added service accounts and deprecations.

[micbar]

closes #739

[ScharfViktor]

LGTM from my side)

[butonic]

What about #679?

We deprecated ocis storage-users uploads list (it still works) and introduced ocis storage-users uploads sessions

[micbar]

@butonic Can you create a separate PR please?

[mmattel]

We deprecated ocis storage-users uploads list

@micbar @butonic
This is two fold:

1. The updated command needs to be documented in the storage-users service.
2. We need to add this change here into the migration docs

I will take care.

UPDATE

• (2) is done
• Also got mentioned in the release notes in the deprecation section