Create page to edit Dancer Metadata

[awltux]

A dancer has a set of Metadata that describes their current roles and positions within the square.
This can be added explicitly to the XML, but if it's incorrect, it would require re-releasing.
Provide a screen that allows permitted users to modify the statically defined roles and positions a dancer inherits as they enter a particular formation/arrangement.

[awltux]

Added new DB table "dancer_metadata" to track metadata specific to formation_position and arrangement. As a Square enters a particular state, the roles and positions can now be searched e.g. who are centres, ends, heads, sides etc.

[awltux]

FIX: Added "sequence_index" and "arrangement_index" columns to "formation_position" to support embedded formations in calls.
formations.xml also contains arrangement (assumed to be "Normal", but highly unlikely to be true for all formations). When embedded formations are used in Calls, the order of the formation and paths is often out of sync with the "Normal" formation.
Embedded formations and the call paths are now re-ordered according to the "Normal" formation order and the arrangement_index.