* in markdown files, use code fences rather than indented blocks.
This is harder to screw up (one of them was off by a space so didn't
render properly) and allows me to add info strings.
* uniformly use "useradd" to create the user and group in all three
places (install-manual.md, script-functions.sh, Dockerfile) rather
than addgroup + adduser. Create a full home dir, which I suspect was
the problem in #67. Don't allow customizing group name; it's always
the same as the user.
* install the sqlite3 package so that the "moonfire-nvr sql" command
works properly.
* remove "setup_db" function, which was out of place. Since the
creation of the "moonfire-nvr init" command, this has to happen
after installation of the binary. install.md gives instructions on
this part anyway so remove it from the script.
* give a proper command to create the db dir. It was creating it
within the current directory, not within /var/lib/moonfire-nvr.
Don't bother creating sample directory; "moonfire-nvr config"
will do this.
* when setting owners on a newly created directory, use a single
"install -d" command rather than "mkdir" + "chown".
* address confusion about whether sample file dirs need to be
precreated. (Only when Moonfire NVR doesn't have write permissions
on the parent.)
* always just install the packaged version of ffmpeg rather than
building our own. This has been usable since Debian/Raspbian 9
Stretch; Debian/Raspbian 10 Buster is out now so there's no excuse
for still running Debian/Raspbian 8 Jessie.
* don't chown the UI directory; it can be owned by root as with
the binary.
* in scripts/install.sh, don't enable/start the service yet. It hasn't
been configured.
* Dockerfile which allows full build on ubuntu
* No cross-compile yet
* Fixed build scripts bug found with docker
Signed-off-by: Dolf Starreveld <dolf@starreveld.com>