Hierarchical folder structure

Switched to the new hierarchical folder structure where a TLD has a folder and the domain is split by single letters. How many prefix letters will depend on the domain name density. We are starting with 2. Example:

root/
root.xml
de.xml
de/
_.xml
y/
_.xml
a/
yam.xml
_.xml

Also: a hierarchy for IP4 addresses:

_ip4/
_.xml
80/
_.xml
154/
_.xml
16/
_.xml
235/
_.xml

TLD files still contain the individual configs. They will be migrated to the folder structure on demand.

Schema firebat-2.7.7

Migrate to firebat-2.7.7 schema. (<delegate> now separate from <location>)