Wal e recovery

Add LWRP for wal-e envdir.
Add seperate recovery and archive recipes for wal-e.

@mbautin 
@vnivargi 
A shorter variant:

```ruby
when (node['postgresql']['wal_e']['s3_path'] || '') =~ /^[sS]3:/
```

Also I prefer `=~` for regex matching (perhaps due to my Perl background :). At least it does not create ambiguity between the array/hash indexing and regex matching.