Refactor the Linux service_enable() method

* Fix check_mode for initctl systems

Fixes #9009
remove debugging that was causing failure
Move delegate_to out of runner module_vars to prevent bleeding across runs

Previously, the delegate_to value was stored in the module_vars of runner,
which could lead to bleeding that value across runs and incorrect hosts
being delegated to. This patch moves the value to a local variable in
the Runner class with some related refactoring of _compute_delegate() in
Runner (since the value is no longer required to be a parameter).

Fixes #8705
Allow filtering by availability zone for exact_count with ec2

Fixes #8863
[#9048] convert Route53 TTL to integer before comparison

boto/Route53 are returning TTL as a string.
The route53 module is comparing it with an integer and therfore thinks the DNS entry has always changed.
Update rax root pubkey example

The example was showing how to use the `files` option to pass in a local file as an authorized public key for root. While this works, it's a bit sloppy, given that there's a specific option, `key_name` which will use one of your public keys on your rackspace account and add it as an authorized key for root. In our case, one of our admins didn't notice the `key_name` option because they scrolled straight to the example and saw the `files` strategy.

I propose that the example still shows `files`, but not using a root public key as an example, and instead also demonstrate the `key_name` option so that it's clear from the example how to get the initial root public key deployed.
Updating current ansible version on docsite index
Merge pull request #9049 from omadahealth/issue_9048

[#9048] convert Route53 TTL to integer before comparison
Merge pull request #9052 from EvanDotPro/docs/fix-rax-public-key-example

Update rax root pubkey example
minor tweak to required modules for running tests
Merge pull request #9058 from mpeters/docsite_more_test_modules

minor tweak to documentation of required modules for running tests
documenting extra packages that need to be installed to run the full integration tests
Failure to enable a service now fails the task

Fixes: 8855
Fix the var we're checking in the upstart test
Fix the name of the upstart service
Allow with_first_files to search relative to templates and vars in roles

Fixes #8879
Merge pull request #9059 from mpeters/docsite_test_integration_packages

documenting extra packages that need to be installed to run the full integration tests