pkgbase: generate dependencies in generate-ucl.sh

[kevans]

Summary

This cuts out a large chunk of duplicated *.ucl files that just needed dependencies tacked on, and gives generate-ucl.sh some leeway in case a future pkg may need more than one dependency.

Run-through to determine which ones could simply be removed done with for i in *.ucl; do diff -U3 template.ucl ${i}; done | less and inspecting for any differences beyond just adding deps at the end. The remaining ucl files are basically all differently-licensed or require scripts.

I've opted to remove %PKGDEPS% entirely without regard for third-party ucl, as pkgbase is not yet considered production. However, I do not hold a strong position on this and there is approximately 0 chance it will return.

Test Plan

Run make packages and observe output .ucl.

root@viper:/usr/obj/usr/src/amd64.amd64/worldstage# cat acct.ucl
#
# $FreeBSD$
#

name = "FreeBSD-acct"
origin = "base"
version = "13.0.s20200129192615"
comment = "Accounting Utilties"
categories = [ base ]
maintainer = "[e-mail]"
www = "https://www.FreeBSD.org"
prefix = "/"
licenselogic = "single"
licenses = [ BSD2CLAUSE ]
desc = <<EOD
Accounting Utilties
EOD
deps: {
        FreeBSD-runtime: {
                origin: "base",
                version: "13.0.s20200129192615"
        }
}

[kevans]

Reinstate clibs exception to having dependencies, which was previously done by having just copied the template over to clibs.ucl and I axed it in rS357257 (along with docs.ucl, but we don't seem to have a -docs pkg anymore).

Things are still fine in head/ today, but they wouldn't be after this change as generate-ucl tacks on the -runtime dependency.