chore(license): add license and authors list

AUTHORS

+Below follows a list of people, who contributed their code and efforts.
+
+Alexander Tolstoy
+Denis Smirnov
+Dmitriy Koltsov
+Dmitriy Travyan
+Igor Kuznetsov
+
+NOTE: If you can commit a change to this list, please do not hesitate
+to add your name to it.

Cargo.toml

@@ -2,8 +2,7 @@
 name = "sbroad"
 version = "0.1.0"
 authors = [
-    "Denis Smirnov <sd@picodata.io>",
-    "Igor Kuznetsov <kuznetsovin@gmail.com>",
+    "Picodata"
 ]
 edition = "2021"
 

LICENSE

+Copyright 2021-2022 Picodata AUTHORS: please see AUTHORS file.
+
+Redistribution and use in source and binary forms, with or
+without modification, are permitted provided that the following
+conditions are met:
+
+1. Redistributions of source code must retain the above
+   copyright notice, this list of conditions and the
+   following disclaimer.
+
+2. Redistributions in binary form must reproduce the above
+   copyright notice, this list of conditions and the following
+   disclaimer in the documentation and/or other materials
+   provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY AUTHORS ``AS IS'' AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGE.