Use .cache subdir for caching

mkit.ini

     etc_bc  = /etc/bash_completion.d
 
 [vars]
-    __SATURNIN_CACHE_HOME__     = $HOME/.local/share/satcmd
+    __SATURNIN_CACHE_HOME__     = $HOME/.cache/satcmd
     __SATURNIN_CONFIG_USER__    = $HOME/.satcmd
     __SATURNIN_CONFIG_LOCAL__   = [roots:etc]
     __SATURNIN_LIBEXEC__        = [roots:libexec]