Allow customizing package name

[MeteorsLiu]

Currently, we don't have a field for customizing package name, however, some library may require different name for PC usage.

Design

use user-provided directory name for module path instead of package.name in llpkg.cfg.

Release-as should follow module path name/semver instead of package.name/semver

[MeteorsLiu]

This will cause a problem:

how to build the binding relationship between custom module path and C library (aka package.name in llpkg.cfg)

[MeteorsLiu]

This will cause a problem:

how to build the binding relationship between custom module path and C library (aka package.name in llpkg.cfg)

cc @aofei @luoliwoshang