Change bahavior of trust anchor

Change bahavior of trust anchor

- Trust-anchor certificate file directory has fixed.
- Make symbolic link when given pkg type is wgt or hybrid.
- When updating wgt/hybrid pkg, previous symlink will be removed.
- Register and update trust anchor have integrated.

Related changes:
[pkgmgr-info] : https://review.tizen.org/gerrit/149784
[wgt-backend] : https://review.tizen.org/gerrit/149978
[tpk-manifest-handlers] : https://review.tizen.org/gerrit/150060
[wgt-manifest-handlers] : https://review.tizen.org/gerrit/150136

Change-Id: Ibdfc760bcb15da324e7237b8b0a5a9103effc129
Signed-off-by: Junghyun Yeon <jungh.yeon@samsung.com>