Replaces mustache template with a theme specified using
Home Manager options. This removes the need for separate
templates for TOML and YAML formats.
The new colors better align with other terminal modules (e.g. wezterm),
and base24 schemes with bright- mnemonics are now supported.
Closes#341.
Since version 0.13.0 alacritty has switched to TOML config
file format. For backwards compatibility this patch implements conditional
template format depending on the package version.
Closes#214
