Error checking and reporting on interface ufw rule

Added quotes around key path - Issue 7713

Escape backslash in assemble module docs

Fix neutron floating IP allocation for networks w/ multiple subnets

Docker links need alias specified

If no alias is passed one will now be created for you with the same name
as the target link container, as per the documentation

Fixed handling of paths containing whitespaces in the synchronize module

nova_keypair should fail if 'name' of key exists in keystore, but ssh hash value != public_key offered

Improve the ec2_snapshot argument spec and docs

Set keepalive to 5 seconds in paramiko_ssh.py

Fix incorrect argument ordering in error message

Ensure random jinja filter doesn't get cached in loops.

printf-related TypeError.

Add environmentfilter to random filter, to ensure the result doesn't get cached. Mirrors default jinja filter.

Fix documentation of deb option in apt module

Update intro_installation.rst

bigip_monitor bugfix for check mode

Fixes #7528

This is different wording for using the PPA to install.  I also added the installation of apt-add-repository package which isn't always installed.

(I'm a newbie but while running these I wished whatever style was being used on the docs pages would have let me  cut and paste the commands without having to edit out the $ characters manually....)

For networks that have both a v4 and a v6 subnet, the floating IP plugin
currently has two problems:

* When determining the subnet for the provided `internal_network_name`, it
assumes that the first item in the list of subnets is the one you want.
Instead, it should pick the first v4 subnet.

* When multiple fixed IP's exist for a given port (as is the case in a network
a v4 and a v6 subnet), neutron needs a hint as to which fixed IP to associate
to the floating IP address (the v4 one).

* Fixed error messages to be more descriptive
* Removed direct use of subprocess module and replaced it with calls
  to module.run_command
* Changed AZURE_MANAGEMENT_CERT_PATH to be just AZURE_CERT_PATH, which
  matches what is expected by the inventory script