kernel_options: add Docker section

Validated with:
- https://github.com/moby/moby/blob/master/contrib/check-config.sh

These kernel options have purposely not been defaulted as =y in the
kernel_options file. These will report as (missing):
- CONFIG_MEMCG_SWAP
- CONFIG_CGROUP_HUGETLB
- CONFIG_RT_GROUP_SCHED
- CONFIG_SECURITY_SELINUX
- CONFIG_SECURITY_APPARMOR
- CONFIG_AUFS_FS

"btrfs" - configured separately
"zfs" - configured separately

distributions/LibreELEC/kernel_options

@@ -44,13 +44,13 @@ CONFIG_INOTIFY_USER=y
 CONFIG_SIGNALFD=y
 CONFIG_TIMERFD=y
 CONFIG_EPOLL=y
-CONFIG_NET=y
+# CONFIG_NET=y # already set in packages/network/wireguard
 CONFIG_SYSFS=y
 CONFIG_PROC_FS=y
 CONFIG_FHANDLE=y
-CONFIG_CRYPTO_USER_API_HASH=y
-CONFIG_CRYPTO_HMAC=y
-CONFIG_CRYPTO_SHA256=y
+# CONFIG_CRYPTO_USER_API_HASH=y # already set in packages/network/iwd
+# CONFIG_CRYPTO_HMAC=y # already set in packages/network/iwd
+# CONFIG_CRYPTO_SHA256=y # already set in packages/network/iwd
 CONFIG_SYSFS_DEPRECATED=n
 CONFIG_UEVENT_HELPER=n
 CONFIG_FW_LOADER_USER_HELPER=n
@@ -78,3 +78,74 @@ CONFIG_NLS_UTF8=y
 # Human Interface Device (HID)
 CONFIG_HID_NINTENDO=m
 CONFIG_NINTENDO_FF=y
+
+# Docker
+CONFIG_NAMESPACES=y
+CONFIG_NET_NS=y
+CONFIG_PID_NS=y
+CONFIG_IPC_NS=y
+CONFIG_UTS_NS=y
+# CONFIG_CGROUPS=y # already set in packages/sysutils/systemd
+CONFIG_CGROUP_CPUACCT=y
+CONFIG_CGROUP_DEVICE=y
+CONFIG_CGROUP_FREEZER=y
+CONFIG_CGROUP_SCHED=y
+CONFIG_CPUSETS=y
+CONFIG_MEMCG=y
+# CONFIG_KEYS=y # already set in packages/network/iwd
+CONFIG_VETH=m
+CONFIG_BRIDGE=m
+CONFIG_BRIDGE_NETFILTER=m
+# CONFIG_IP_NF_FILTER=m # already set in netfilter
+# CONFIG_IP_NF_TARGET_MASQUERADE=m # already set in netfilter
+CONFIG_NETFILTER_XT_MATCH_ADDRTYPE=m
+CONFIG_NETFILTER_XT_MATCH_CONNTRACK=m
+CONFIG_NETFILTER_XT_MATCH_IPVS=m
+CONFIG_NETFILTER_XT_MARK=m
+# CONFIG_IP_NF_NAT=m # already set in netfilter
+CONFIG_NF_NAT=m
+CONFIG_POSIX_MQUEUE=y
+# CONFIG_CGROUP_BPF=y # already set in packages/sysutils/systemd
+CONFIG_USER_NS=y
+# CONFIG_SECCOMP=y # already set in packages/sysutils/systemd
+# CONFIG_SECCOMP_FILTER=y # already set in packages/sysutils/systemd
+CONFIG_CGROUP_PIDS=y
+CONFIG_BLK_CGROUP=y
+CONFIG_BLK_DEV_THROTTLING=y
+CONFIG_CGROUP_PERF=y
+CONFIG_NET_SCHED=y
+CONFIG_NET_CLS_CGROUP=m
+CONFIG_CGROUP_NET_PRIO=y
+CONFIG_CFS_BANDWIDTH=y
+CONFIG_FAIR_GROUP_SCHED=y
+CONFIG_IP_NF_TARGET_REDIRECT=m
+CONFIG_IP_VS=m
+CONFIG_IP_VS_NFCT=y
+CONFIG_IP_VS_PROTO_TCP=y
+CONFIG_IP_VS_PROTO_UDP=y
+CONFIG_IP_VS_RR=m
+# CONFIG_EXT4_FS=y # already set in general
+# CONFIG_EXT4_FS_POSIX_ACL=y # already set in packages/sysutils/systemd
+CONFIG_EXT4_FS_SECURITY=y
+CONFIG_VXLAN=m
+CONFIG_BRIDGE_VLAN_FILTERING=y
+CONFIG_CRYPTO=y
+CONFIG_CRYPTO_AEAD=y
+CONFIG_CRYPTO_GCM=y
+CONFIG_CRYPTO_SEQIV=y
+CONFIG_CRYPTO_GHASH=y
+CONFIG_XFRM=y
+CONFIG_XFRM_USER=y
+CONFIG_XFRM_ALGO=y
+CONFIG_INET_ESP=y
+CONFIG_IPVLAN=m
+CONFIG_MACVLAN=m
+CONFIG_DUMMY=m
+CONFIG_NF_NAT_FTP=m
+CONFIG_NF_CONNTRACK_FTP=m
+CONFIG_NF_NAT_TFTP=m
+CONFIG_NF_CONNTRACK_TFTP=m
+CONFIG_MD=y
+CONFIG_BLK_DEV_DM=m
+CONFIG_DM_THIN_PROVISIONING=m
+CONFIG_OVERLAY_FS=m