Is your feature request related to a problem? Please describe.
In modpacks and environments with multiple tech mods, multiple versions of the fluids used by Tech Reborn's fluid generators can be present, and often are, and modpack makers cannot change what these generators accept as fuel to my knowledge. Likewise, those looking to make these generators accept more unusual fluids for their own silly ideas cannot do so to my knowledge.

Describe the solution you'd like
The semi-fluid generator, gas turbine, thermal generator, plasma generator and diesel generator would use fluid tags to determine what fluids can be used to power them. End users and modpack developers could add fluids to data/techreborn/tags/fluids/semi_fluid_generator_fuels.json, for example, to add fluids that the semi-fluid generator can use, with similar tags for the other four fluid generators.

Describe alternatives you've considered
Alternatively, Tech Reborn's configuration files could accept lists of fluid ids that they accept, that are then passed along to the generators internally, if it is impossible to make them accept fluid tags. This approach wouldn't let the usable fluids be modified via datapacks, however, and I personally prefer the vanilla approach of using tags, but it's no big difference either way.

Additional context
Tech Reborn is great about letting aspects of itself such as its machines' energy values and all of its recipes be configured. I thought this would be not too big an ask to add to that configurability.