refactoring

- overlays/{linux,wine-osu}.nix -> packages/{linux-lava,wine-osu}/
- overlays/misc/ -> overlays/patches/
- overlays/misc/0001...patch -> packages/linux-lava/si...patch
- overlays/misc/wine/ -> packages/wine-osu/patches/
- flake.nix:
  - overlays are dynamically read from overlays/
  - define custom packages separately
- packages/*
  - now imported using callPackage

overlays/misc/wine/0003-secur32-Fix-crash-from-invalid-context-in-Initialize.patch

@@ -1,26 +0,0 @@
-From e17fb0bda3c042beec05b918e2d171211742e01c Mon Sep 17 00:00:00 2001
-From: Torge Matthies <openglfreak@googlemail.com>
-Date: Fri, 12 Feb 2021 13:58:35 +0100
-Subject: [PATCH 3/4] secur32: Fix crash from invalid context in
- InitializeSecurityContextW.
-
-Signed-off-by: Torge Matthies <openglfreak@googlemail.com>
----
- dlls/secur32/schannel.c | 1 +
- 1 file changed, 1 insertion(+)
-
-diff --git a/dlls/secur32/schannel.c b/dlls/secur32/schannel.c
-index 9c7e98b32a4c55588a78ac6c3811b89db9e09db7..b2baefbc8caaf370c9c0ec31b7daf4cc9bb7fbb8 100644
---- a/dlls/secur32/schannel.c
-+++ b/dlls/secur32/schannel.c
-@@ -983,6 +983,7 @@ static SECURITY_STATUS SEC_ENTRY schan_InitializeSecurityContextW(
-         unsigned char *ptr;
- 
-         ctx = schan_get_object(phContext->dwLower, SCHAN_HANDLE_CTX);
-+        if (!ctx) return SEC_E_INVALID_HANDLE;
-         if (pInput)
-         {
-             idx = schan_find_sec_buffer_idx(pInput, 0, SECBUFFER_TOKEN);
--- 
-2.32.0
-