Cleaning imports of the waku store module (#673)

* cleans up store modules

* removes endians2 as an unused imports

* reorganizes imports

* fixes an ambiguous import

* adds comments re imports order

* adds message_store

waku/v2/node/jsonrpc/jsonrpc_utils.nim

@@ -61,7 +61,7 @@ proc toWakuRelayMessage*(message: WakuMessage, symkey: Option[SymKey], privateKe
   let
     keyInfo = if symkey.isSome(): KeyInfo(kind: Symmetric, symKey: symkey.get()) 
               elif privateKey.isSome(): KeyInfo(kind: Asymmetric, privKey: privateKey.get())
-              else: KeyInfo(kind: None)
+              else: KeyInfo(kind: KeyKind.None)
     decoded = decodePayload(message, keyInfo)
 
   WakuRelayMessage(payload: decoded.get().payload,

waku/v2/protocol/waku_store/waku_store.nim

@@ -4,21 +4,36 @@
 
 {.push raises: [Defect].}
 
+# Group by std, external then internal imports
 import
+  # std imports
   std/[tables, times, sequtils, algorithm, options],
+  # external imports
   bearssl,
-  chronos, chronicles, metrics, stew/[results, byteutils, endians2],
+  chronicles,
+  chronos, 
   libp2p/crypto/crypto,
   libp2p/protocols/protocol,
   libp2p/protobuf/minprotobuf,
   libp2p/stream/connection,
+  metrics,
+  stew/[results, byteutils],
+  # internal imports
   ../../node/storage/message/message_store,
-  ../waku_swap/waku_swap,
-  ./waku_store_types,
+  ../../node/peer_manager/peer_manager,
   ../../utils/requests,
-  ../../node/peer_manager/peer_manager
+  ../waku_swap/waku_swap,
+  ./waku_store_types
+  
 
-export waku_store_types, message_store
+# export all modules whose types are used in public functions/types
+export 
+  options,
+  chronos,
+  bearssl,
+  minprotobuf,
+  peer_manager,
+  waku_store_types
 
 declarePublicGauge waku_store_messages, "number of historical messages", ["type"]
 declarePublicGauge waku_store_peers, "number of store peers"

waku/v2/protocol/waku_store/waku_store_types.nim

@@ -1,17 +1,28 @@
 ## Types for waku_store protocol.
 
+# Group by std, external then internal imports
 import
+  # external imports
   bearssl,
   libp2p/peerinfo,
   libp2p/protocols/protocol,
-  ../waku_swap/waku_swap_types,
-  ../waku_message,
+  stew/results,
+  # internal imports
   ../../node/storage/message/message_store,
   ../../utils/pagination,
-  ../../node/peer_manager/peer_manager
+  ../../node/peer_manager/peer_manager,
+  ../waku_swap/waku_swap_types,
+  ../waku_message
 
-export waku_message
-export pagination
+# export all modules whose types are used in public functions/types
+export 
+  bearssl,
+  results,
+  peer_manager,
+  waku_swap_types,
+  message_store,
+  waku_message,
+  pagination
 
 # Constants required for pagination -------------------------------------------
 const MaxPageSize* = uint64(100) # Maximum number of waku messages in each page