static checks should support recursive dirs

[johntdyer]

I might want to organize my static checks in folders but the feature currently doesnt support recursive search into folders. This would be a nice thing to have

[johntdyer]

FWIW I now get this error, which I think is new for 0.6.0

WARN [autokuma::sync] Encountered error during sync: Unable to deserialize: Unsupported static monitor file type: /static/adsb, supported: .json, .toml
WARN [autokuma::sync] Encountered error during sync: Unable to deserialize: Unsupported static monitor file type: /static/adsb, supported: .json, .toml
WARN [autokuma::sync] Encountered error during sync: Unable to deserialize: Unsupported static monitor file type: /static/adsb, supported: .json, .toml
WARN [autokuma::sync] Encountered error during sync: Unable to deserialize: Unsupported static monitor file type: /static/adsb, supported: .json, .toml
WARN [autokuma::sync] Encountered error during sync: Unable to deserialize: Unsupported static monitor file type: /static/adsb, supported: .json, .toml
WARN [autokuma::sync] Encountered error during sync: Unable to deserialize: Unsupported static monitor file type: /static/adsb, supported: .json, .toml

[BigBoot]

Yes, static monitors still do not support recursive search, I'm hesitant to add this because the filename is used as the id and i'm not sure something like <dir>/<filename> would be a good fit for the id

[BigBoot]

This has been fixed on master, please note that the master currently contains some breaking change so make sure to read the CHANGELOG if you want to test the feature.