This commit is applied only to v4.0.

Part 1:

This change gets rid of the TransactionReaper's usage of the
ReplicationCoordinator for checking whether it is primary or not and
makes the LogicalSessionCache joinable on shutdown.

It also removes the TransactionReaper's grouping per-shard optimization
and moves it all under SessionCollectionSharded.

(cherry picked from commit 2791817876636c0cfd60d867f31c7a83cf3f18c1)

Part 2:

This change folds the TransactionReaper's single function to be part of
the SessionCatalogs on MongoD and MongoS, which are the subsystems
responsible for managing transactions.

(cherry picked from commit 94f269a1c6053824c4dabc50e8c9219b80a6a1b5)
(cherry picked from commit 7e6a80789cd74f9b533065f57afb5c9221eea1e7)

(cherry picked from commit bf4a3cff4dc5572f2e97cb5279fe63c8227187e0)

SERVER-39936 Use PeriodicRunner handles to simplify shutdown ordering

(cherry picked from commit 1eff33bd1a8d48eb607675f87faf1836ba325006)

This is a partial backport. Parts of the original commits listed do not
exist in v4.0

(cherry picked from commit 1fb52e97b33c6c4ed7855994aeb7c4c4a7e64b1d)

This patch does several loosely related and surprisingly hard to separate things.

1.) Make the ServiceContext class final

2.) Create a mechanism, called ConstructorActions, for running methods on
ServiceContexts immediately after they're built and immediately before they're
destroyed.

3.) Introduce / improve test fixture base classes for tests, giving them fresh
ServiceContext instances for each test case. There is one fixture for tests that
need a storage engine and another for those that do not.

4.) Make several remaining global variables SC decorations in support of (3)

5.) Replace many MONGO_INITIALIZERS that access getGlobalServiceContext with the
new constructor-actions system, which is needed for (3.)

6.) Fix up tests to use the fixtures from (3) and fix tests that silently used
different service contexts in together in a technically illegal fashion that now
breaks.

7.) Utilize (2) as necessary to simplify initialization of new ServiceContexts,
simplifying the fixtures in (3).

(cherry picked from commit d520be0814492c262515cf0a5d62a127ace70dce)

SERVER-35985 Destroy clients started in other threads.

(cherry picked from commit 9a68eb0cc65a93233b4ff5746330f9eb77de9b90)

SERVER-36258 Construct ServiceContext after mongo initializers complete.

(cherry picked from commit bfe170e49b1dc10b2badde45bc13c057a2f8ab61)

SERVER-36400 Explicitly destroy the client on exiting run() of each BackgroundJob

(cherry picked from commit b079e4713d897b5541c2804386025817ec720800)

SERVER-36351 Fix so ServiceContextMongoDTest removes the temp directory in its destructor.

(cherry picked from commit 4c16f0f336f4db77034e8aa594bbd4a5bac3f40c)

SERVER-36347 Fix parse_zone_info.py after ServiceContext refactor.

(cherry picked from commit c9d4204b6243e5eee6fe0b5e2c34d02af9ac5edb)

The Authorization framework was intertwined with many subsystems and
needed to be properly abstracted in order to facilitate cutting down
on certain unnecessary dependencies in some libraries.  This also
facilitates creating a reduced authorization framework for use
in embedded builds.

Replace PeriodicRunnerASIO with PeriodicRunnerImpl, a simpler interface
that runs jobs on dedicated threads.