genrest: De-spam docs by skipping direct deps. in more places

Similar deal to commit cc14c40a ("kconfiglib: Unclutter symbol
strings, avoid redundant writes, misc.").

Hide the direct dependencies in the defaults, selects, and implies
sections. Do the same in menuconfig/guiconfig as well.

This uses a new Kconfiglib API, so update Kconfiglib to upstream
revision 164ef007a8. This also includes some minor optimizations and
cleanups.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>