Portduino packaging: Move meshtastic/web out of `/usr/share/doc`

[vidplace7]

/usr/share/doc is the home of documentation on most Linux distros. On minimal / embedded distros (such as buildroot) this directory is often removed by default to save disk space; akin to stripping manpages.

This PR moves meshtasticd/web out of /usr/share/doc and into /usr/share on Portduino platforms.

Includes a symlink from the new location to the previous location, to ease the transition. https://manpages.debian.org/testing/debhelper/dh_link.1.en.html

[fifieldt]

@vidplace7 new error in package after merging this

sed -E s,^refs/tags/,,
+ INPUT_VERSION=2.5.12.4a11437
+ [ -z  ]
+ du --bytes --summarize --exclude=DEBIAN .debpkg/
+ awk {print $1}
+ PACKAGE_ROOT_SIZE_BYTES=69938[17](https://github.com/meshtastic/firmware/actions/runs/11793227510/job/32849279279?pr=5322#step:9:18)6
+ INPUT_INSTALLED_SIZE=68299
+ /replacetool --debian-dir:/template/DEBIAN --package:meshtasticd --version:2.5.12.4a11437 --installed-size:68299 --depends:libyaml-cpp0.7, openssl, libulfius2.7 --homepage:none --arch:amd64 --maintainer:Jonathan Bennett --description:Native Linux Meshtastic binary.
+ cp -r /template/DEBIAN .debpkg/
+ echo 2.5.12.4a11437
+ sed -E s/^v//
+ FIXED_VERSION=2.5.12.4a11437
+ readonly FIXED_VERSION
+ OWNER=--root-owner-group
+ [ false = true ]
+ readonly DEB_FILE=meshtasticd_2.5.12.4a11437_amd64.deb
+ dpkg-deb -Zgzip --root-owner-group --build .debpkg meshtasticd_2.5.12.4a11437_amd64.deb
dpkg-deb: error: maintainer script 'preinst' has bad permissions 644 (must be >=0555 and <=0775)