Prepare for release v1.7.11

[christarazi]

Summary of Changes

Minor Changes:

• Add metric 'cilium_k8s_event_lag_seconds' for calculated lag of Kubernetes events (Backport PR v1.7 backports 2020-10-23 #13739, Upstream PR pkg/endpoint: calculate Kube API-Server lag from pod events #13702, @aanm)
• Automatic rate limiting of endpoint API calls (Backport PR v1.7 backports 2020-10-02 #13392, Upstream PR Automatic rate limiting of endpoint API calls #13319, @tgraf)

Bugfixes:

• bpf: only clean up XDP from devices with XDP attached (Backport PR v1.7 backports 2020-10-15 #13595, Upstream PR bpf: only clean up XDP from devices with XDP attached #13532, @jaffcheng)
• contexthelpers: Fix deadlock when nobody recvs on success channel (Backport PR v1.7 backports 2020-10-07 #13441, Upstream PR contexthelpers: Fix deadlock when nobody recvs on success channel #13408, @brb)
• endpoint: Avoid benign error messages on restoration (Backport PR v1.7 backports 2020-10-22 #13708, Upstream PR endpoint: Avoid benign error messages on restoration #13667, @pchaigno)
• Fix bug where Cilium leaks a goroutine when an endpoint is deleted. This leak, if left running in a high pod churn environment, can cause Cilium to exceed its memory usage and get OOM killed. (Backport PR v1.7 backports 2020-10-21 #13690, Upstream PR endpoint: Fix goroutine leak when EP is deleted #13683, @christarazi)
• identity: Fix nil pointer panic in LookupIdentityByID (Backport PR v1.7 backports 2020-10-15 #13595, Upstream PR identity: Fix nil pointer panic in LookupIdentityByID #13514, @gandro)
• lbmap: Correct issue that port info display error (Backport PR v1.7 backports 2020-10-23 #13721, Upstream PR lbmap: Correct issue that port info display error #13244, @Jianlin-lv)
• metrics: fix negative identity count (Backport PR v1.7 backports 2020-10-23 #13721, Upstream PR metrics: fix negative identity count #12313, @ArthurChiao)
• reduce cardinality of prometheus labels (Backport PR v1.7 backports 2020-10-22 #13708, Upstream PR pkg/endpoint: reduce cardinality of prometheus labels #13699, @aanm)
• service: Use initNextID in acquireLocalID() (Backport PR v1.7 backports 2020-10-15 #13595, Upstream PR service: Use initNextID in acquireLocalID() #13576, @hzhou8)

CI Changes:

• bugtool: get bpffs mountpoint from /proc/mounts (Backport PR v1.7 backports 2020-10-05 #13402, Upstream PR bugtool: get bpffs mountpoint from /proc/mounts #13342, @jibi)

Misc Changes:

• backporting: Update labels by default when submitting backport (Backport PR v1.7 backports 2020-10-22 #13708, Upstream PR backporting: Update labels by default when submitting backport #13703, @pchaigno)
• contrib: Improve start-release.sh script (Backport PR v1.7 backports 2020-10-05 #13402, Upstream PR contrib: Improve start-release.sh script #13357, @joestringer)
• docs: Add a note about systemd 245 rp_filter issue (Backport PR v1.7 backports 2020-10-23 #13739, Upstream PR docs: Add a note about systemd 245 rp_filter issue #13717, @brb)
• docs: Fix TLS visibility GSG (Backport PR v1.7 backports 2020-10-09 - fix TLS visibility GSG #13487, Upstream PR docs: Fix TLS visibility GSG #13452, @jrajahalme)
• endpoint: Avoid logging about disconnected EPs during restore (Backport PR v1.7 backports 2020-10-22 #13708, Upstream PR endpoint: Avoid logging about disconnected EPs during restore #10974, @jrajahalme)
• Fix race condition in DeepEqual function (Backport PR v1.7 backports 2020-10-09 - Race condition in DeepEqual function #13491, Upstream PR Fix race condition in DeepEqual function #13472, @aanm)
• Follow-up fixes for the API rate limiter (Backport PR 1.7 backports 2020-10-08 - API rate limiting fixes #13477, Upstream PR Follow-up fixes for the API rate limiter #13450, @tgraf)
• fsnotify: correctly check for event operation (Backport PR v1.7 backports 2020-10-05 #13402, Upstream PR fsnotify: correctly check for event operation #13325, @kaworu)
• Improve documentation of filtering unnecessary labels (Backport PR v1.7 backports 2020-10-23 #13721, Upstream PR pkg/labelsfilter: add more unit test and rewrite docs #13696, @aanm)
• k8s: update k8s libraries to 1.17.13 (k8s: update k8s libraries to 1.17.13 #13652, @aanm)
• test: Debug RuntimeConntrackInVethModeTest flake (Backport PR v1.7 backport 2020-10-20 #13656, Upstream PR test: Debug RuntimeConntrackInVethModeTest flake #13295, @pchaigno)
• test: Replace managed etcd test with generic etcd test (Backport PR [v1.7] test: Replace managed etcd test with generic etcd test #13574, Upstream PR test: Replace managed etcd test with generic etcd test #11544, @tgraf)
• vagrant: Only set K8S_NODE_NAME if K8S=1 (Backport PR v1.7 backports 2020-10-05 #13402, Upstream PR vagrant: Only set K8S_NODE_NAME if K8S=1 #11086, @jrajahalme)

Other Changes:

• [v1.7] Dockerfile: Bump cilium-runtime image ([v1.7] Dockerfile: Bump cilium-runtime image #13789, @christarazi)
• [v1.7] document option for enabling API rate limiting ([v1.7] document option for enabling API rate limiting #13422, @qmonnet)