tools: move get-developers out of support/scripts/

Move it to the top-level tools/ directory, so that it is easier to
find for users.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

docs/manual/contribute.txt

@@ -295,7 +295,7 @@ information). This tool reads your patches and outputs the appropriate
 +git send-email+ command to use:
 
 ---------------------
-$ ./support/scripts/get-developers outgoing/*
+$ ./tools/get-developers outgoing/*
 ---------------------
 
 Use the output of +get-developers+ to send your patches:

tools/readme.txt

@@ -2,6 +2,11 @@ This directory contains various useful scripts and tools for working
 with Buildroot. You need not add this directory in your PATH to use
 any of those tools, but you may do so if you want.
 
+get-developpers
+    a script to return the list of people interested in a specific part
+    of Buildroot, so they can be Cc:ed on a mail. Accepts a patch as
+    input, a package name or and architecture name.
+
 test-pkg
     a script that tests a specific package against a set of various
     toolchains, with the goal to detect toolchain-related dependencies