nsc: Expose generalized build materials in xdump and conditionals

nsc: Expose generalized build materials in xdump and conditionals

Ship, plane, land unit and nuke types require lcms and hcms to build.
Planes also require military, and nukes also require oil and rads.
These build materials are exposed as ship-chr, plane-chr, land-chr,
nuke-chr selectors l_build, h_build, crew, o_build, r_build.

We want to optionally support more build materials in the future.  To
help clients prepare for that, provide selectors for all other item
types.  Use CA_DUMP_ONLY to keep them out of configuration tables
until they actually work.

Rename selector crew to m_build for consistency.  This is an xdump
compatibility break.  We could easily add m_build and deprecate crew
to provide the customary grace period for such breaks.  However, more
xdump changes are coming down the pipe, and for some of them providing
a grace period wouldn't be as easy.  Ron Koenderink assures us WinACE
doesn't need a grace period.  So don't bother with maintaining xdump
compatibility in this release.

Signed-off-by: Markus Armbruster <armbru@pond.sub.org>