- concerns
- dashboard
- groups
- import

[master] Fixed read private group names

See merge request gitlab/gitlabhq!2589

Enables frozen string for the following:

* app/controllers/dashboard/**/*.rb
* app/controllers/explore/**/*.rb
* app/controllers/google_api/**/*.rb
* app/controllers/groups/**/*.rb
* app/controllers/import/**/*.rb
* app/controllers/instance_statistics/**/*.rb
* app/controllers/ldap/**/*.rb
* app/controllers/oauth/**/*.rb
* app/controllers/profiles/**/*.rb

Partially addresses #47424.

This whitelists all existing offenses for the various CodeReuse cops, of
which most are triggered by the CodeReuse/ActiveRecord cop.

This reverts commit 8717c7dad9b5a8fa21ec9a652c54718a6b4c2175.

This reverts commit 4d9a3f42f1fd3be21555e19872b7121cca65015e, reversing
changes made to ecf9c145f6e4d170cd059df88743393d9e63c489.

* Group filtering now includes also issues/MRs from
subgroups/subprojects
* fixed due_date
* Also DRYed todo controller specs

Rails 5.0 requires to explicitly permit attributes when building a URL
using current `params` object.

The `safe_params` helper allows developers to just call `safe_params.merge(...)`
instead of manually adding `permit` to every call.

https://github.com/rails/rails/pull/20868

The todos page limit is 20, and both that and a user's pending todo count are
integers. Using integer division means that the result's floor will be taken,
defeating the point of the later call to `#ceil`.

So we need to convert one side of the division to a float first, otherwise the
last page won't be treated as available.

When there are no filters, we can get the total todos count from the cached
count on the user object, instead of performing a DB query. This query takes
about 80ms for me on GitLab.com.