Override palette in config

[GordianDziwis]

Is your feature request related to a problem? Please describe.
The heuristics for defining the base palette do not work for my color schema.

Describe the solution you'd like
Being able to set the base palette as a config option

Describe alternatives you've considered
Hard-code my palette in hl.lua

local function make_palette()
  local bg     = Color.from_hex(get_bg("Normal") or "#151515")
  local fg     = Color.from_hex("#D0D0D0")
  local red    = Color.from_hex("#FF0086")
  local orange = Color.from_hex("#FD8900")
  local yellow = Color.from_hex("#ABA800")
  local green  = Color.from_hex("#00C918")
  local cyan   = Color.from_hex("#1FAAAA")
  local blue   = Color.from_hex("#3777E6")
  local purple = Color.from_hex("#AD00A1")

  local config = require("neogit.config")

  local bg_factor = vim.o.bg == "dark" and 1 or -1
...

[CKolkey]

Reasonable enough, sure.