The fs_query component queries and monitors information stored on a file
system. The file system is configured as a component-local VFS. The component
accepts any number of '<query>' nodes within its '<config>' node. Each
'<query>' node must contain a 'path' attribute pointing to a directory to
watch. The component generates a report labeled "listing". For each
existing queried directory, the report contains a '<dir>' node with the
list of files as '<file>' nodes featuring the corresponding 'name' as
attribute value.

A '<query>' can be equipped with a 'content="yes"' attribute. If set, the
content of the queried files is supplemented as body of the '<file>' nodes.
The reported content is limited to 4 KiB per file. If the content is valid
XML, the '<file>' node contains an attribute 'xml="yes"' indicating that
the XML information is inserted as is. Otherwise, the content is sanitized.

If the query attribute 'count="yes"' is set, the reported '<dir>' nodes
deliver an overview of the directory content as attributes 'num_dirs',
'num_files', and 'num_symlinks'.

Furthermore, a query can contain a 'size="yes"' attribute. If set, the size of
each queried file is reported as number of bytes through an attribute 'size' in
the corresponding '<file>' node.
