Use shlex for parsing policy::Table

[markafarrell]

This replaces the current approach for parsing policy (space delimited) with shlex. This allows us to include spaces in policy fields.

This is important for:

• policy matching for groups that include spaces
• the future use of CEL

shlex does NOT support quoting fields that include spaces and as a result doing something like:

e.g.

t := NewTable("1 \"2 3\" 4") // [ [ "1", "2 3", "4" ] ]
s := t.ToString() // "1 2 3 4"
t1 := NewTable(s) // [ [ "1", "2", "3", "4"] ]

It this is important we can use shellquote

[markafarrell]

It looks like it is critical that we preserve the quoting as it is used to write the policy file so I think we are better off using shellquote #158 instead

[yonatan-sevenai]

This implementation is broken since it uses shlex to read tables but join(row, " ") to write.
This means that writing oidc:groups:some group will read oidc:group:some as the write function won't add the proper escape functions. The shellquote approach #158 looks more complete.

See my comment here

[EthanHeilman]

Do we want to close this? It sounds like everyone wants shellquote instead?

[yonatan-sevenai]

As long as we're comfortable with the background compatibility, yes - shellquote would be superior.

[markafarrell]

Close as shellquote is better