* Reprovider strategy: rename "flat" to "all".
Value "flat" now parses to "all". Behaviour from "all" removed.
Fixes#10864 which has detailed explanation.
* core/node/provider.go: remove unused function mfsRootProvider
It was used in the "all" strategy.
* docs: improve reprovider.strategy=all changelog framing
- highlight memory efficiency improvements
- clarify this removes v0.28 workaround
- update config.md memory requirements
- fix announce-on profile typo
* feat: deprecate Reprovider.Strategy=flat
- add deprecation warning in daemon.go when flat strategy is detected
- document that flat is deprecated in ParseReproviderStrategy comment
- add explicit test case for flat -> all mapping
- flat continues to work but users are warned to migrate to all
---------
Co-authored-by: Marcin Rataj <lidel@lidel.org>
846e219ead