libmalcontent: Add a SessionLimits interface for time-limited sessions

This is another extension interface on accountsservice which stores
information about time and usage limits on the user session. Currently,
only a ‘daily schedule’ limit (or no limit) is supported, but additional
types and combinations of limits can be supported in future.

The daily schedule limit allows using the computer between a certain
start time and end time each day (the same each day). The user will be
kicked out of their session when the end time is reached, if they
haven’t already logged out.

This includes the getters for the new data, polkit rules for accessing
it, and some documentation. Changes to `malcontent-client` to support
session limits, setters, and unit tests will all follow.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

libmalcontent/meson.build

@@ -3,14 +3,17 @@ libmalcontent_api_name = 'malcontent-' + libmalcontent_api_version
 libmalcontent_sources = [
   'app-filter.c',
   'manager.c',
+  'session-limits.c',
 ]
 libmalcontent_headers = [
   'app-filter.h',
   'malcontent.h',
   'manager.h',
+  'session-limits.h',
 ]
 libmalcontent_private_headers = [
   'app-filter-private.h',
+  'session-limits-private.h',
 ]
 
 libmalcontent_public_deps = [