Project: remove old/deprecated feature flags (#12356)

These flags are not used in the code anymore.

Author: humitos

readthedocs/projects/models.py

@@ -1964,13 +1964,8 @@ def add_features(sender, **kwargs):
 
     # Dependencies related features
     PIP_ALWAYS_UPGRADE = "pip_always_upgrade"
-    USE_NEW_PIP_RESOLVER = "use_new_pip_resolver"
-    DONT_INSTALL_LATEST_PIP = "dont_install_latest_pip"
-    USE_SPHINX_RTD_EXT_LATEST = "rtd_sphinx_ext_latest"
-    INSTALL_LATEST_CORE_REQUIREMENTS = "install_latest_core_requirements"
 
     # Search related features
-    ENABLE_MKDOCS_SERVER_SIDE_SEARCH = "enable_mkdocs_server_side_search"
     DEFAULT_TO_FUZZY_SEARCH = "default_to_fuzzy_search"
 
     # Build related features
@@ -2021,24 +2016,7 @@ def add_features(sender, **kwargs):
         ),
         # Dependencies related features
         (PIP_ALWAYS_UPGRADE, _("Build: Always run pip install --upgrade")),
-        (USE_NEW_PIP_RESOLVER, _("Build: Use new pip resolver")),
-        (
-            DONT_INSTALL_LATEST_PIP,
-            _("Build: Don't install the latest version of pip"),
-        ),
-        (
-            USE_SPHINX_RTD_EXT_LATEST,
-            _("Sphinx: Use latest version of the Read the Docs Sphinx extension"),
-        ),
-        (
-            INSTALL_LATEST_CORE_REQUIREMENTS,
-            _("Build: Install all the latest versions of Read the Docs core requirements"),
-        ),
         # Search related features.
-        (
-            ENABLE_MKDOCS_SERVER_SIDE_SEARCH,
-            _("Search: Enable server side search for MkDocs projects"),
-        ),
         (
             DEFAULT_TO_FUZZY_SEARCH,
             _("Search: Default to fuzzy search for simple search queries"),