Users no longer need to explicitly generate configuration source code as
they are now generated at build time. This patch updates the relevant
instructions in the documentation.
v3:
* RELEASE now defaults to n.
* Cleanup the unnecessary target `all` in the `make` commands
* Remove menuconfig related stuff.
* Refine the introductory paragraph as only steps on Ubuntu is introduced
* Also introduce the targets introduced by PR #5791
v2:
* Add python3 lxml as a dependency
* Explain how to use out-of-tree XML files
Tracked-On: #5644
Signed-off-by: Junjie Mao <junjie.mao@intel.com>
Co-authored-by: Geoffroy Van Cutsem <geoffroy.vancutsem@intel.com>
9b4bf5e2a8