Xposed API v100 support

[fox8091]

As of 2363b80, Xposed API v101 support was implemented. However, at this time, the latest stable release of Vector (open source fork of LSPosed) only supports API v100.

During this transitional period, I feel it would be best to support both API v100 and API v101 as was done in the builds from #500, at least until a Vector build including JingMatrix/Vector@a7d97a6 is released, preferably with a deprecation window after its' release to give users on the Play Store build adequate time to update their modules.

[kavishdevar]

I originally didn't want to support v100 because it'd need adding another build variant/flavor and I already have 2*2 variants (play/FOSS+normal/xposed). But since Google has allowed the xposed version to be published. I can add a variant with v100 as well. I'll keep this open until I implement it.