add build script that helps to speed up development

build_core_dev.sh

 #!/bin/bash
 
+# This script is meant to be used during development of any component related to bitmaskcore
+# Make sure you have run build_core.sh at least once before using this script, so that
+# golang dev environment is correctly setup, all patches have been applied to the submodules etc.
+# This script only builds the different go submodules together as they are currently checked out.
+
 RED='\033[0;31m'
 GREEN='\033[0;32m'
 NC='\033[0m'
@@ -13,65 +18,9 @@ function showtitle {
     echo -e "\n\n${GREEN}--- $1 ...${NC}\n"
 }
 
-# -------- install golang ---------------
-showtitle "Installing golang"
-
-if [[ "$OSTYPE" == "linux-gnu"* ]]; then
-        GO_VERSION=go1.19.8.linux-amd64
-        EXPECTED_FP=e1a0bf0ab18c8218805a1003fd702a41e2e807710b770e787e5979d1cf947aba
-elif [[ "$OSTYPE" == "darwin"* ]]; then
-        # Mac OSX
-        ARCH=`uname -a | rev | cut -d " " -f 1 | rev`
-        if [[ "$ARCH" = "x86_64" ]]; then
-            GO_VERSION=go1.19.8.darwin-amd64
-            EXPECTED_FP=d63e12909b3639df24f2614284868869ce14fdea2059ed365752da82ca59f994
-        else
-            GO_VERSION=go1.19.8.darwin-arm64
-            EXPECTED_FP=12df6263329794c55b1d63160cda9dd62de4ecd65fe52ddca33bc96a57c38ea6
-        fi
-else
-        echo "$OSTYPE is currently not supported."
-        exit 1
-fi
-
-
-if [[ $(ls -A ${GO_VERSION}.tar.gz) ]]
-then
-    echo "Reusing downloaded golang bundle"
-else
-    echo "Installing go lang bundle ${GO_VERSION}.tar.gz from https://golang.org/dl/$GO_VERSION.tar.gz"
-    curl -L -o "${GO_VERSION}.tar.gz" "https://golang.org/dl/${GO_VERSION}.tar.gz"
-    if [[ "$OSTYPE" == "linux-gnu"* ]]; then
-      ACTUAL_FP=`sha256sum $GO_VERSION.tar.gz | cut -d " " -f1`
-    else
-      ACTUAL_FP=`shasum -a 256 $GO_VERSION.tar.gz | cut -d " " -f1`
-    fi
-
-    if [[ ! $ACTUAL_FP == $EXPECTED_FP ]]
-    then
-        quit "Download seems to be corrupted. Cancelling build."
-    fi
-fi
-
-if [[ -d ./golang ]]
-then
-    if [[ $(ls -A ./golang/*) ]]
-    then
-        rm -r ./golang/*
-    fi
-else
-    mkdir ./golang
-fi
-tar -C ./golang -xzf $GO_VERSION.tar.gz || quit "Could not untar $GO_VERSION.tar.gz"
-
-
-# -------- update submodules ---------------
-showtitle "Updating submodules"
-# git submodule sync --recursive || quit "git submodule sync --recursive"
-# git submodule update --init --recursive || quit "git submodule update --init --recursive"
-
-
 # -------- init environment variables ---------------
+
+showtitle "Initializing go environment"
 cd ./golang
 export GOPATH=`pwd`
 export GO_LANG=`pwd`/go/bin
@@ -82,40 +31,6 @@ go env -w GOFLAGS=-mod=mod
 go env
 cd ..
 
-# -------- init gomobile ---------------
-showtitle "Getting gomobile"
-#./golang/go/bin/go install golang.org/x/mobile/cmd/gomobile || quit "./golang/go/bin/go install golang.org/x/mobile/cmd/gomobile"
-
-showtitle "initiating gomobile"
-#./golang/bin/gomobile init || quit "./golang/bin/gomobile init"
-
-
-# -------- prepare snowflake ---------------
-showtitle "Checking out snowflake repository"
-cd ./IPtProxy/snowflake
-git checkout --force --quiet 36f03dfd4483922b3e7400dedc71df9cf2f30b6b || quit "Failed to checkout snowflake at commit 36f03dfd4483922b3e7400dedc71df9cf2f30b6b"
-git submodule update --init --recursive || quit "Failed to update snowflake submodules"
-cd ..
-
-showtitle "Applying patches to snowflake"
-patch --directory=snowflake --strip=1 < snowflake.patch || quit 
-cd ..
-
-showtitle "Applying patch to IPtProxy"
-patch --directory=IPtProxy --strip=1 < iptproxy.patch || quit
-
-# -------- preparing obfsvpn ---------------
-showtitle "Applying patch to obfsvpn"
-patch --directory=obfsvpn --strip=1 < obfsvpn.patch || quit
-
-# -------- preparing shapeshifter ---------------
-showtitle "Applying patch to shapeshifter"
-patch --directory=shapeshifter --strip=1 < shapeshifter.patch || quit
-
-# -------- preparing motd ---------------
-showtitle "Applying patch to motd (message of the day)"
-patch --directory=motd --strip=1 < motd.patch || quit
-
 
 # -------- build core ---------------