Ftr: add triple 'msgpack' codec support, and user defined serializer support.

[LaurenceLiZhixin]

What this PR does:

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov-commenter]

Codecov Report

Merging #1242 (ff11800) into 3.0 (968650f) will decrease coverage by 3.59%.
The diff coverage is 50.60%.

@@            Coverage Diff             @@
##              3.0    #1242      +/-   ##
==========================================
- Coverage   59.53%   55.93%   -3.60%     
==========================================
  Files         259      272      +13     
  Lines       12737    12886     +149     
==========================================
- Hits         7583     7208     -375     
- Misses       4199     4779     +580     
+ Partials      955      899      -56     

Impacted Files	Coverage Δ
cluster/cluster_impl/available_cluster_invoker.go	66.66% <ø> (ø)
cluster/cluster_impl/broadcast_cluster_invoker.go	76.47% <ø> (ø)
cluster/cluster_impl/failfast_cluster_invoker.go	66.66% <ø> (ø)
cluster/cluster_impl/mock_cluster.go	0.00% <0.00%> (ø)
cluster/loadbalance/random.go	100.00% <ø> (ø)
...router/v3router/judger/list_string_match_judger.go	0.00% <0.00%> (ø)
...ster/router/v3router/judger/method_match_judger.go	0.00% <0.00%> (ø)
...er/router/v3router/judger/url_label_match_judge.go	0.00% <0.00%> (ø)
common/extension/auth.go	0.00% <ø> (ø)
common/extension/cluster.go	0.00% <ø> (ø)
... and 277 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b5cd555...ff11800. Read the comment docs.

[zhaoyunxing92]

approved these changes