[GUI] Replace lump in S1 BSP with lump from LMP file

[SirYodaJedi]

Describe Your Suggestion

You mentioned on Discord that the backend supports this, but there isn't a GUI (or CLI) method for doing this yet.

Looking at lumpfileheader_t, it seems S1 LMP files store what lump they replace, so the only error checking I can think would be necessary would be making sure lumpLength is correct (if the value found at that position isn't, it probably is an IdTech LMP instead).