samples: boards: Merge nrf91/ with nrf52/ and rename it to nrf/

The following samples:
- boards/nrf91/nrfx
- boards/nrf52/power_mgr
are actually not specific to nRF91 and nRF52 Series SoCs, respectively,
hence the current naming of the above board/ subdirectories may be
misleading. Thus, use nrf/ directory for holding all nRF board specific
samples that apply to several boards.

Paths to the moved samples that are mentioned in their documentation
are also updated accordingly.

Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>

samples/boards/nrf/mesh/onoff-app/prj.conf

@@ -0,0 +1,103 @@
+#CONFIG_INIT_STACKS=y      # if set, lots of noise from mesh/adv.c: STACK_ANALYZE
+CONFIG_MAIN_STACK_SIZE=512
+CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
+
+CONFIG_GPIO=y
+
+CONFIG_BT_SETTINGS=y
+CONFIG_FLASH=y
+CONFIG_FLASH_PAGE_LAYOUT=y
+CONFIG_FLASH_MAP=y
+CONFIG_NVS=y
+CONFIG_SETTINGS=y
+CONFIG_BT_MESH_RPL_STORE_TIMEOUT=600
+
+CONFIG_BOOT_BANNER=y
+
+CONFIG_BT_OBSERVER=y
+CONFIG_BT_BROADCASTER=y
+CONFIG_BT_CTLR_DUP_FILTER_LEN=0
+CONFIG_BT_CTLR_LE_ENC=n
+CONFIG_BT_CTLR_LE_PING=n
+CONFIG_BT_DATA_LEN_UPDATE=n
+CONFIG_BT_PHY_UPDATE=n
+CONFIG_BT_CTLR_CHAN_SEL_2=n
+CONFIG_BT_CTLR_MIN_USED_CHAN=n
+CONFIG_BT_CTLR_ADV_EXT=n
+CONFIG_BT_CTLR_PRIVACY=n
+
+CONFIG_BT_PERIPHERAL=y
+
+CONFIG_BT=y
+CONFIG_BT_TINYCRYPT_ECC=y
+CONFIG_BT_L2CAP_RX_MTU=69
+CONFIG_BT_L2CAP_TX_MTU=69
+CONFIG_BT_L2CAP_TX_BUF_COUNT=8
+
+CONFIG_BT_MESH=y
+CONFIG_BT_MESH_RELAY=y
+CONFIG_BT_MESH_LOW_POWER=n
+CONFIG_BT_MESH_FRIEND=n
+CONFIG_BT_MESH_FRIEND_QUEUE_SIZE=16
+CONFIG_BT_MESH_ADV_BUF_COUNT=20
+CONFIG_BT_MESH_TX_SEG_MAX=6
+
+CONFIG_BT_MESH_PB_GATT=y
+CONFIG_BT_MESH_PB_ADV=y
+CONFIG_BT_MESH_GATT_PROXY=y
+CONFIG_BT_MESH_CFG_CLI=y
+
+#CONFIG_BT_MESH_LPN_SCAN_LATENCY=30
+#CONFIG_BT_MESH_LPN_RECV_DELAY=40
+#CONFIG_BT_MESH_LPN_POLL_TIMEOUT=300
+
+CONFIG_BT_MESH_SUBNET_COUNT=2
+CONFIG_BT_MESH_APP_KEY_COUNT=2
+CONFIG_BT_MESH_MODEL_KEY_COUNT=2
+CONFIG_BT_MESH_MODEL_GROUP_COUNT=2
+CONFIG_BT_MESH_LABEL_COUNT=3
+
+#CONFIG_BT_MESH_IV_UPDATE_TEST=y
+
+CONFIG_UART_CONSOLE=y
+
+# this outputs btmon formatted data to the serial port
+#CONFIG_BT_DEBUG_MONITOR=y
+
+CONFIG_BT_DEBUG_LOG=y
+
+CONFIG_BT_MESH_DEBUG=y
+#CONFIG_BT_MESH_DEBUG_PROV=y
+#CONFIG_BT_MESH_DEBUG_PROXY=y
+#CONFIG_BT_MESH_DEBUG_BEACON=y
+#CONFIG_BT_MESH_DEBUG_NET=y
+#CONFIG_BT_MESH_DEBUG_TRANS=y
+#CONFIG_BT_MESH_DEBUG_LOW_POWER=y
+#CONFIG_BT_MESH_DEBUG_FRIEND=y
+#CONFIG_BT_MESH_DEBUG_MODEL=y
+#CONFIG_BT_MESH_DEBUG_ACCESS=y
+#CONFIG_BT_MESH_DEBUG_CRYPTO=y
+#CONFIG_BT_MESH_DEBUG_ADV=y
+#CONFIG_BT_MESH_SELF_TEST=y
+
+#CONFIG_BT_HCI_VS_EXT=n
+
+#CONFIG_STACK_USAGE=y
+
+CONFIG_BT_RX_STACK_SIZE=4096
+
+#CONFIG_BT_DEBUG_HCI_DRIVER=y
+#CONFIG_BT_DEBUG_HCI_CORE=y
+#CONFIG_BT_DEBUG_GATT=y
+#CONFIG_BT_DEBUG_CONN=y
+
+CONFIG_BT_MAX_CONN=1
+CONFIG_BT_CTLR_RX_BUFFERS=6
+CONFIG_BT_CTLR_TX_BUFFERS=4
+CONFIG_BT_HCI_CMD_COUNT=4
+
+CONFIG_BT_ATT_PREPARE_COUNT=2
+
+#CONFIG_NET_BUF_SIMPLE_LOG=y
+#CONFIG_NET_BUF_LOG=y
+#CONFIG_BT_CTLR_DEBUG_PINS=y