Blacklist H803

H803 isn't supported by community consensus. Blacklist it to avoid
breaking folk's muscle memory.

Change-Id: I8eea9eb2562e12136018e762c8a5e23527fcf48f
Document the dangers of co-existing elements.

Add a potent example (and simply remedy) of how element authors can
unwittingly conflict with each other in ways that it is almost
impossible for us to guard against with low level policy/mechanism in
di-b. Fixes bug 1181309.

Change-Id: I51e845065702911371e448521327143495c3b405
Remove explicit sudoers requirement.

Most of our build process runs as root and the overhead of explicitly
tracking sudo commands in the shipped sudoers.d file, plus the
operational overhead of keeping the sudoers.d file updated on build
hosts over time, is now considered to be unnecessary.
Instead, we now document that the build process will expect sudo
commands to work and the operator must make this happen (either by
running as root, via sudo -E, or allowing passwordless sudo for the
build user).

Change-Id: If2628e7d0c7efde0fb99c84a217523ba29b1b38d
Merge "Document the dangers of co-existing elements."
Merge "Remove explicit sudoers requirement."