x11-wm/bvwm: new port

[dteske]

Summary

BVWM is a fork of fvwm3. This port stages only the renamed core
binary (bin/bvwm) and RUN_DEPENDS on stock fvwm3 for modules,
share data, and man pages.

Includes ButtonStyle hover and TitleStyle ButtonWidth; defaults to
~/.bvwm / .bvwmrc so stock fvwm3 configs stay untouched.

Test Plan

$ make
$ make package
$ pkg install -f work/pkg/bvwm-1.1.5.2.pkg
$ pkg list bvwm

Should yield:

/usr/local/bin/bvwm
/usr/local/share/licenses/bvwm-1.1.5.2/GPLv2
/usr/local/share/licenses/bvwm-1.1.5.2/LICENSE
/usr/local/share/licenses/bvwm-1.1.5.2/catalog.mk

Then:

$ pkg info -R bvwm | awk '/fvwm3:/,/}/'

Which should yield:

fvwm3: {
    origin: "x11-wm/fvwm3",
    version: "1.1.5_1"
},

[dteske]

Do not package BREADME.md / BCHANGELOG.md (match fvwm3).

[dteske]

Bump to 1.1.5-bvwm.2; drop meson.build ports patch.