move charset plugins to c

[gogo2464]

Description

Please describe what are you missing or wanting to be improved

I created charset plugin in text format. I was focusing in user usability... and felt to windows philosophy instead of unix philosophy!!! It did not follows r2 philosophy. I would like to rewrite it as C plugin.I did not have enough r2 xp when doing this first PR. I must change it!!!

I would like to replace the txt charset plugin charset to a C charset modularity system for custom charset.

Assign me to this issue please.

Provide images, ascii-art, test files and anything that may help us understand your request

[trufae]

Unix philosophy implies plain text files before compiled code. The only resson for c plugins here would be to handle cases not possible with k=v. no need to assign anything, feel free to submit a proposal of the api and usecases