Fix dependencies, use spaces instead of tabs in .spec file, rename
`imapdomo.spec` to `template.spec`, rename `imapdomo.install` to
`install`, remove unnecessary `override_dh_auto_install`, add URL to
.spec, update Summary, clean up.

Overview of changes:

 *  Simplified configuration

The host split turned to be a vast overengineering.

Overview of changes:

 *  Fixed initial errors caused bu migration from mydots
 *  Fixed packaging

We don't run .lua scripts directly; we use imapfilter which solves its
own dependencies (uses liblua5).

Overview of changes:

 *  Added everything