avoid confusing with salt-cloud
rewrite some sentences
add document for installing salt-cloud on Ubuntu

as saying that salt cloud is merged to Salt may cause confusing
make user thinks no need to install salt-cloud pkg
add basic usage doc for salt-cloud
Consolidate duplicate bind docs of docker.running

The documentation for `docker.running` had two divergent definitions for the `bind` argument. I've consolidated them and added some explanation of the two forms.
Clean keyboard exit in test suite
Add missing <ul>[…]</ul> around list elements in sidebar TOC.
Updated the contributing guide with a link to the documentation contribution docs.
Fixed some spacing issues in the contributing docs.
Don't calculate sum on stat
Small pylint fix in salt.daemons.flo.core
Merge pull request #14107 from rallytime/pylint_fix

Small pylint fix in salt.daemons.flo.core
Merge pull request #14083 from hvnsweeting/hvn-doc-update

Salt virt/cloud doc update
Merge pull request #14092 from eykd/patch-2

Consolidate duplicate bind docs of docker.running
Merge pull request #14100 from cachedout/test_exit

Clean keyboard exit in test suite
Merge pull request #14101 from eliasp/docs-toc-list-ul

Add missing <ul>[…]</ul> around list elements in sidebar TOC.
Merge pull request #14102 from gravyboat/develop

Link documentation guide in contributing guide.
Merge pull request #14105 from cachedout/11538

Don't calculate sum on stat
Better fix for #11538

The other one is valid too, since we don't need the sum in this
run anyway. But we should kill all get_sum calls or make get_sum call
get_hash
flag lxc as beta