E2E: Rename end-to-end-tests-server to grafana-server (#44249)

* Rename to grafana-server / move scripts into new directory

* Change grafana-server step command

* Change scripts paths

* Use test grabpl version

* Update run-suite script

* Further name updates

* Update grabpl version

* Update contribute/style-guides/e2e-core.md

Co-authored-by: Maria Alexandra <239999+axelavargas@users.noreply.github.com>

Co-authored-by: Maria Alexandra <239999+axelavargas@users.noreply.github.com>

scripts/grafana-server/variables

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+DEFAULT_RUNDIR=scripts/grafana-server/tmp
+RUNDIR=${RUNDIR:-$DEFAULT_RUNDIR}
+HOME_PATH=$PWD/$RUNDIR
+PIDFILE=$RUNDIR/pid
+DEFAULT_PACKAGE_FILE=dist/grafana-*linux-amd64.tar.gz
+PROV_DIR=$RUNDIR/conf/provisioning
+DEFAULT_HOST=localhost
+DEFAULT_PORT=3001