Add ability to override the character symbols used to represent an Entity Reference as a string

@Role
public interface SymbolScheme
{
    /**
     * @return the character used for escaping characters in Entity Reference names
     */
    Character getEscapeSymbol();

    /**
     * @return the map containing all the symbols to separate Entity Types. The map's key is an Entity Type and
     *         the value is another map who's key is the second Entity Type and its value is the character separating
     *         the 2 Entity Types. For example you could have the {code .} character separating an
     *         {@link EntityType#DOCUMENT} and a {@link EntityType#SPACE}. Note that a given Entity Type can have
     *         several separator characters if it can have several different parent types (e.g. a Space reference can
     *         have either a Space Entity Type or a Wiki Entity Type)
     */
    Map<EntityType, Map<EntityType, Character>> getSeparatorSymbols();

    /**
     * @param type the Entity Type for which to get the list of strings to escape. For example for a SPACE Entity type
     *             you could want to escape {@code .}, {@code :} and {@code \}.
     * @return the various strings that require escaping for the passed Entity type
     */
    String[] getSymbolsRequiringEscapes(EntityType type);

    /**
     * @param type the Entity Type for which to get the list of strings to use to replace each escape returned by
     *             {@link #getSymbolsRequiringEscapes(EntityType)}. For example for a SPACE Entity type you could
     *             want to replace {@code .} with {@code \.}, {@code :} with  {@code \:} and {@code \} with {@code \\}
     * @return the various replacement strings to replace string that require escaping
     */
    String[] getReplacementSymbols(EntityType type);
}