Today, if the aliases file does not exist when chasquid starts up, the entire
domain will be skipped from aliases resolution.
That's a bug, as it means we don't perform character and suffix replacements
for known domains, and is also an inconvenience as it forces us to reload the
daemon when adding a file for a known domain.
This patch fixes this by adding them unconditionally, even if the file does
not exist.
This patch removes chasquid-userdb and adds a more generic and extensive
chasquid-util, that supports various operations on user databases as well as
aliases lookups.
The code is not very pretty but for now I took a more practical approach, the
tool is ancillary and can be tidied up later.
aliases databases can be very useful, so this patch adds a package to parse
and resolve aliases.
It uses an existing, well known and widely used format for aliases, although
it doesn't necessarily match 100% any existing implementation at the moment.
