feat(out-of-office): Add OCS endpoint to set and clear absence

[nickvergessen]

• Resolves: Out of office: expose setting endpoint via OCS #41458

TODO

• Add OCS endpoint so that clients can set this in the future
• Migrate frontend to OCS endpoint
• Remove unused index.php endpoint

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[provokateurin]

OpenAPI looks good

[ChristophWurst]

Sure

[nickvergessen]

Had forgotten the autoloader update on the removal commit, force pushed that:

diff --git a/apps/dav/composer/composer/autoload_classmap.php b/apps/dav/composer/composer/autoload_classmap.php
index ef28133ed06..5d6b077ad53 100644
--- a/apps/dav/composer/composer/autoload_classmap.php
+++ b/apps/dav/composer/composer/autoload_classmap.php
@@ -193,7 +193,6 @@ return array(
     'OCA\\DAV\\Connector\\Sabre\\SharesPlugin' => $baseDir . '/../lib/Connector/Sabre/SharesPlugin.php',
     'OCA\\DAV\\Connector\\Sabre\\TagList' => $baseDir . '/../lib/Connector/Sabre/TagList.php',
     'OCA\\DAV\\Connector\\Sabre\\TagsPlugin' => $baseDir . '/../lib/Connector/Sabre/TagsPlugin.php',
-    'OCA\\DAV\\Controller\\AvailabilitySettingsController' => $baseDir . '/../lib/Controller/AvailabilitySettingsController.php',
     'OCA\\DAV\\Controller\\BirthdayCalendarController' => $baseDir . '/../lib/Controller/BirthdayCalendarController.php',
     'OCA\\DAV\\Controller\\DirectController' => $baseDir . '/../lib/Controller/DirectController.php',
     'OCA\\DAV\\Controller\\InvitationResponseController' => $baseDir . '/../lib/Controller/InvitationResponseController.php',
diff --git a/apps/dav/composer/composer/autoload_static.php b/apps/dav/composer/composer/autoload_static.php
index 73e680ef2e8..2456604a9cb 100644
--- a/apps/dav/composer/composer/autoload_static.php
+++ b/apps/dav/composer/composer/autoload_static.php
@@ -208,7 +208,6 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\Connector\\Sabre\\SharesPlugin' => __DIR__ . '/..' . '/../lib/Connector/Sabre/SharesPlugin.php',
         'OCA\\DAV\\Connector\\Sabre\\TagList' => __DIR__ . '/..' . '/../lib/Connector/Sabre/TagList.php',
         'OCA\\DAV\\Connector\\Sabre\\TagsPlugin' => __DIR__ . '/..' . '/../lib/Connector/Sabre/TagsPlugin.php',
-        'OCA\\DAV\\Controller\\AvailabilitySettingsController' => __DIR__ . '/..' . '/../lib/Controller/AvailabilitySettingsController.php',
         'OCA\\DAV\\Controller\\BirthdayCalendarController' => __DIR__ . '/..' . '/../lib/Controller/BirthdayCalendarController.php',
         'OCA\\DAV\\Controller\\DirectController' => __DIR__ . '/..' . '/../lib/Controller/DirectController.php',
         'OCA\\DAV\\Controller\\InvitationResponseController' => __DIR__ . '/..' . '/../lib/Controller/InvitationResponseController.php',

[nickvergessen]

/backport to stable28

[nickvergessen]

Backport in #41963