Why this change?
Back in May 17 2023 along with the release of Discourse 3.1, we announced
on meta that the legacy hamburger dropdown navigation menu is
deprecated and will be dropped in Discourse 3.2. This is the link to the announcement
on meta: https://meta.discourse.org/t/removing-the-legacy-hamburger-navigation-menu-option/265274
## What does this change do?
This change removes the `legacy` option from the `navigation_menu` site
setting and migrates existing sites on the `legacy` option to the
`header dropdown` option.
All references to the `legacy` option in code and tests have been
removed as well.
According to the output of this rake task:
`LOAD_PLUGINS=0 bin/rails "site_settings:find_dead"`
which searches for unused site settings, these settings:
```
rate_limit_new_user_create_topic
enable_system_avatars
check_for_new_features
allow_user_api_keys
```
are unused.
* DEV: move sidebar community section to database
Before, community section was hard-coded. In the future, we are planning to allow admins to edit it. Therefore, it has to be moved to database to `custom_sections` table.
Few steps and simplifications has to be made:
- custom section was hidden behind `enable_custom_sidebar_sections` feature flag. It has to be deleted so all forums, see community section;
- migration to add `section_type` column to sidebar section to show it is a special type;
- migration to add `segment` column to sidebar links to determine if link should be displayed in primary section or in more section;
- simplify more section to have one level only (secondary section links are merged);
- ensure that links like `everything` are correctly tracking state;
- make user an anonymous links position consistence. For example, from now on `faq` link for user and anonymous is visible in more tab;
- delete old community-section template.
With the introduction of the sidebar navigation menu, the design team at
Discourse redesigned the user profile navigation to better coexist with
the sidebar.
This new site setting replaces the
`enable_experimental_sidebar_hamburger` and `enable_sidebar` site
settings as the sidebar feature exits the experimental phase.
Note that we're replacing this without depreciation since the previous
site setting was considered experimental.
Internal Ref: /t/86563
