upgrade to use units package

[sebkopf]

consider reimplementing on top of the nice units package https://r-quantities.github.io/units/index.html

Note: with the latest version, this would automatically take care of units getting rendered correctly in plots and ggplots

Things to think about for implementation in microbial kitchen:

• will have to implement the autoscaling feature
• will have to find a simple way to set the default base units

[sebkopf]

Implementation details:

• Amount: mole, mol and SI prefixes all work in units package (`set_units(1, "mmole") |> set_units("µmol")
• Mass: g and all SI prefixes work
• Volume: l and L and SI prefixes work
• Temperature: degC, degK (although plain K also works), degF instead of just C/K/F but could be converted in the qty function. Technical mK also works but not sure that's advisable
• Pressure: bar, atm, psi, torr and SI prefixes all supported, % SP would need to be implemented in the qty function to convert to bar (no units with % symbol allowed)
• Molecular Weight: Da is not included but easily added with install_unit("Da", "g/mol", "Dalton") and then all SI prefixes work as well
• Molarity: M is not included but added with install_unit("M", "mol/L", "molarity") and then all SI prefixes and conversions work
• Density: supported
• Gas solubility: with the addition of molarity, this is also automatically supported --> e.g. set_units(760, "mM/bar") |> set_units("M/atm") works

With this, ALL the quantity calculations should work automatically. Also units can be kept the way they are when generating a qty (e.g. keep pressure in psi if entered that way) or can be converted with to_base_units = TRUE (default FALSE) and to_best_prefix = TRUE (default TRUE). Just the carbonate chemistry needs a little more adjustments

--> make sure to issue appropriate depreciation messages for old functions

[sebkopf]

consider adding other useful units like "cell" so that "cell/ml" and "cell/L" automatically work for calculations

[sebkopf]

--> this will be best done in #1 separate chemunits package