Revert "Remove explicit dependency on commons-codec"

This reverts commit 8fec209a6cd20a355141fb33a467f6e7f406eeca.

Reason for revert: This change broke the in-tree build of the
plugin [1].

[1] https://gerrit-ci.gerritforge.com/view/Plugins-stable-2.14/job/plugin-serviceuser-bazel-stable-2.14/25/console

Change-Id: I5bc006af513d42dde100c8cf53d06e2c279c8960
3 files changed