build: introduce luci-base
Merges libs/core, libs/ipkg, libs/web, libs/sys, libs/sgi-cgi, libs/sgi-uhttpd,
modules/admin-core, themes/base and protcols/core into modules/base and renames
luci-lib-core to luci-base.
- [DH] modules/admin-core/luasrc/controller/admin/servicectl.lua
- [DH] modules/admin-core/luasrc/tools/status.lua
- [DH] modules/admin-core/luasrc/tools/webadmin.lua
- [DH] modules/admin-core/luasrc/view/error404.htm
- [DH] modules/admin-core/luasrc/view/error500.htm
- [DH] modules/admin-core/luasrc/view/footer.htm
- [DH] modules/admin-core/luasrc/view/header.htm
- [DH] modules/admin-core/luasrc/view/indexer.htm
- [DH] modules/admin-core/luasrc/view/sysauth.htm