[Sync framework] Disable contacts content change triggered syncs if sync...

[Sync framework] Disable contacts content change triggered syncs if sync interval set to manual only (#1569)

* Fix lint error

Signed-off-by: Sunik Kupfer <kupfer@bitfire.at>

* Show manual sync interval setting in UI

Signed-off-by: Sunik Kupfer <kupfer@bitfire.at>

* Disable contacts content change triggered syncs if set to manual; update kdoc

Signed-off-by: Sunik Kupfer <kupfer@bitfire.at>

* Update comments and kdoc

Signed-off-by: Sunik Kupfer <kupfer@bitfire.at>

* Automatically close provider

Signed-off-by: Sunik Kupfer <kupfer@bitfire.at>

* Explicitly handle special case

* Rename updateAutomaticSync to updateSyncFrameworkSetting; adjust comments

Signed-off-by: Sunik Kupfer <kupfer@bitfire.at>

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Signed-off-by: Sunik Kupfer <kupfer@bitfire.at>
Co-authored-by: Ricki Hirner <hirner@bitfire.at>