Add project path to sql query to build proper path

Add specs for group level

Update entities

Update base classes

Add groups-centric changes

Update plan and review stage

Add summary classes

Add summary spec

Update specs files

Add to specs test cases for group

Add changelog entry

Add group serializer

Fix typo

Fix typo

Add fetching namespace in sql query

Update specs

Add rubocop fix

Add rubocop fix

Modify method to be in sync with code review

Add counting deploys from subgroup

To group summary stage

Add subgroups handling

In group stage summary

Add additional spec

Add additional specs

Add more precise inheritance

Add attr reader to group level

Fix rubocop offence

Fix problems with specs

Add cr remarks

Renaming median method and a lot of calls in specs

Move spec setup

Rename method in specs

Add code review remarks regarding module

Add proper module name

Enables frozens string for the following:

* lib/gitlab/conflict/**/*.rb
* lib/gitlab/cross_project_access/**/*.rb
* lib/gitlab/cycle_analytics/**/*.rb
* lib/gitlab/data_builder/**/*.rb
* lib/gitlab/database/**/*.rb
* lib/gitlab/dependency_linker/**/*.rb
* lib/gitlab/diff/**/*.rb
* lib/gitlab/downtime_check/**/*.rb
* lib/gitlab/email/**/*.rb
* lib/gitlab/etag_caching/**/*.rb

Partially addresses gitlab-org/gitlab-ce#47424.

This removes all usage of soft removals except for the "pending delete"
system implemented for projects. This in turn simplifies all the query
plans of the models that used soft removals. Since we don't really use
soft removals for anything useful there's no point in keeping it around.

This _does_ mean that hard removals of issues (which only admins can do
if I'm not mistaken) can influence the "iid" values, but that code is
broken to begin with. More on this (and how to fix it) can be found in
https://gitlab.com/gitlab-org/gitlab-ce/issues/31114.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/37447

And use .rubocop.yml to exclude paths we don't care,
rather than using the cop itself to exclude.

This reverts commit cb10b725c8929b8b4460f89c9d96c773af39ba6b.