Hide `concurrent` arg for state.sls

This arg should almost never be used, so I don't think it should be
featured in the function signature.  It remains documented in the
docstring, but with a giant warning below it.
Document multiple file.managed sources
Remove references to masterless salt from gitfs docs

Alternate backends do not yet work with the local fileclient.
Clarify a point about runners and eauth
Typo
Merge pull request #15450 from cachedout/file_managed_list

Document multiple file.managed sources
Merge pull request #15453 from terminalmage/remove-masterless-examples

Remove references to masterless salt from gitfs docs
Merge pull request #15456 from cachedout/eauth_clarify

Clarify a point about runners and eauth
Add metadata optio to the parser
Use the metadata option to display the full ret
Add metadata to ssh call
handle the metadata passed back from the caller routine

in salt ssh
refine metadata routine to get the correct data
set the wfuncs to handle the new metadata sent back
Add ssh_minion_cache option
Merge pull request #15465 from thatch45/call_meta

Call meta
Merge pull request #15467 from thatch45/ssh_meta_2

Salt ssh meta data
Merge pull request #15468 from thatch45/ssh_clean_pillar

Ssh clean pillar
Add pygit2 install link to gitfs walkthrough
Merge pull request #15449 from basepi/hideconcurrent

Hide `concurrent` arg for state.sls