Resolve "Perpare patchscript for new lede ENV"

Usage: ./buildscript.sh <command>
command:
  patch                 Apply patches on gluon build ENV
  clean_patches         Remove applied patches from gluon repo
  update-patches        Create patches from local gluon commits
  prepare <command>
    GLUON_BRANCH <str>  Set ENV variable
    GLUON_RELEASE <str> Set ENV variable
    fastd               Prepare site repo for fastd build
    l2tp                prepare site repo for l2tp build
    BROKEN              y or n (default n)
  build <command>       <command> can be replace with targets
    target_list         build all gluon targets
    all                 build all gluon targes for each VPN
  create_manifest       create manifest

Closes #42 (closed) Closes #43 (closed)