webos-image: Switch to non-GPLv3 versions of bash, gzip, readline & tar

:Release Notes:
Switch to the using the busybox editions of bash, gzip, and to v5.2 of
readline and v1.17 of tar.

:Detailed Notes:
- Various scripts have first lines with #!/bin/bash, so configure
  busybox to include a bash applet.
- Use a .bbappend for dhcp to override its explicit RDEPENDS_dhcp-client
  setting to "bash" with "busybox".

:Testing Performed:
Checked rootfs contents.

:QA Notes:

:Issues Addressed:
[GF-43279] Switch to non-GPLv3 versions of various components
[GF-51850] CCC: busybox=webos2 {bash,gzip}=busybox readline=v5.2
           tar=v1.17 (switch to non-GPLv3 versions)

Open-webOS-DCO-1.0-Signed-off-by: Iyad Qumei <iyad.qumei@lge.com>
Change-Id: I9d042442427014c6d51df60939bd56b829dc8dbc
Reviewed-on: https://g2g.palm.com/3923
Reviewed-by: DCO Verification
Reviewed-by: Iyad Qumei <iyad.qumei@lge.com>
Tested-by: Iyad Qumei <iyad.qumei@lge.com>
Reviewed-by: Herb Kuta <herb.kuta@lge.com>
Build: Susan Montooth <susan.montooth@lge.com>
Reviewed-by: Build Verification
Reviewed-by: Susan Montooth <susan.montooth@lge.com>