samba4: update to 4.11.11

samba4: update to 4.11.11

* update to 4.11.11
* fixes CVE-2020-10730, CVE-2020-10745, CVE-2020-10760, CVE-2020-14303
* add fix-musl_missing__nss_buflen_passwd.patch
* remove fixed tirpc include
* add extra CONFIGURE_VARS (XSLTPROC=false, WAF_NO_PREFORK=1)
* fix python3 host paths, ensure we use build hostpkg tools
* add new UCI option "enable_extra_tuning"
* update template
* add config examples for options
* fix some access warnings on samba /var dirs

Signed-off-by: Andy Walsh <andy.walsh44+github@gmail.com>