sing-box-alpha: add optdepends

[DeepChirp]

sing-box can use sing-geosite and sing-geoip to handle routing rules. Therefore, perhaps it would be better to add them as optional dependencies, just like the sing-box package?

[merrkry]

All-in-one geoip/geosite bundles are deprecated by upstream long ago. It is now recommended to use rule_set instead.

[DeepChirp]

All-in-one geoip/geosite bundles are deprecated by upstream long ago. It is now recommended to use rule_set instead.

Yes, you are correct. However, according to the AUR description, taking IP addresses set as an example, both sing-geoip-rule-set and sing-geoip-rule-set-git provide sing-geoip. Therefore, is it reasonable to treat them as optional dependencies?

[merrkry]

Pacman's optional depencies are more of a hint. You can still install whatever you want without these lines.

• Old db data is deprecated by upstream and will be deleted and support will be deleted in future versions. Therefore I deleted them (5ddc015) to discourage new users from using it.
• We might want to package rulesets, but the naming is already chaotic. I would prefer let sing-box optionally depend on sing-rule-sets (something like that, TBD). Point is, it is a completely different format, continuing using the old geo* name will mislead users they are the same, or at least compatible. But rulesets require config migration and are not necessarily related to geodbs.

[DeepChirp]

In fact, I want to install the ruleset as a dependency, which is more semantic.

The official also provides two data types at the same time, and is still being updated - although db has been replaced. In my opinion, we can actually use sing-rule-sets instead of sing-db, but that would require modifying another software package.

[DeepChirp]

@merrkry Due to #4647, the naming of the rule sets seems quite clear. Perhaps sing-geosite-rule-set and sing-geoip-rule-set could be treated as optional dependencies?