Remove spec file

Debian build files were removed in
2e4af77b85.

I think it's good enough if distros ship their build scripts.
No reason to maintain them upstream.

People who are interested can take a look at the openSUSE spec file:
https://build.opensuse.org/package/view_file/network/profanity/profanity.spec

profanity.spec

@@ -1,51 +0,0 @@
-Name:		profanity
-Version:	0.8.1
-Release:	2%{?dist}
-Summary:	A console based XMPP client
-
-Group:		Application/System
-License:	GPL
-URL:		https://profanity-im.github.io/
-Source0:	%{name}-%{version}.tar.gz
-
-BuildRequires:	libstrophe-devel
-# or:
-#BuildRequires:	libmesode-devel
-BuildRequires:	libcurl-devel
-BuildRequires:	ncurses-devel
-BuildRequires:	openssl-devel
-BuildRequires:	glib2-devel >= 2.56.0
-BuildRequires:	expat-devel
-BuildRequires:	libotr-devel
-BuildRequires:	gnutls-devel
-BuildRequires:	sqlite3-devel >= 3.27.0
-BuildRequires:	libsignal-protocol-c-devel >= 2.3.2
-Requires:	libstrophe
-Requires:	libcurl
-Requires:	ncurses-libs
-Requires:	openssl
-Requires:	glib2 >= 2.56.0
-Requires:	expat
-Requires:	libotr
-Requires:	gnutls
-Requires:	sqlite3-devel >= 3.27.0
-Requires:	libsignal-protocol-c-devel >= 2.3.2
-
-%description
-Profanity is a console based XMPP client written in C using ncurses and libstrophe, inspired by Irssi.
-
-%prep
-%setup -q
-
-%build
-%configure
-make %{?_smp_mflags}
-
-%install
-make install DESTDIR=%{buildroot}
-
-%files
-%{_bindir}/profanity
-%doc %{_datadir}/man/man1/profanity.1.gz
-
-%changelog