Rewrite/simplify the template system

[favonia]

Problem

The current template system is working but does not seem to be well-engineered.

1. Currently, the template engine increases the size of the (compressed) image by ~1MB.
2. TTL currently supports templates (for fun), but that is probably overkill.
3. For PROXIED, only Boolean expressions are needed. No need to support variables, template inclusion, looping, etc.

Proposal

1. TTL should not support templates.
2. PROXIED should support only very restricted templates as a Boolean expression consisting of
   a. Constants supported by strconv.ParseBool
   b. &&, ||, !
   b. is(a, b, c)
   c. sub(a, b, c): subdomains of a.b.c (not including a.b.c itself)

Benefits

1. Extremely fast
2. Extremely small (again)
3. No ugly string quotations for domains!

Examples

• is(a.org) || is(b.org)
• sub(org) && !sub(favonia.org)