feat(helper): add eta on progressbar for known-length inputs

[hanxiao]

import time

from jina import DocumentArray, Document, Executor, requests, Flow

da = DocumentArray([Document() for _ in range(100)])

class MyExec(Executor):
    @requests
    def foo(self, **kwargs):
        time.sleep(.1)

with Flow().add(uses=MyExec) as f:
    f.post('/', da, show_progress=True, request_size=1)

[codecov]

Codecov Report

Merging #3688 (c098951) into master (7d9e6fd) will increase coverage by 2.48%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #3688      +/-   ##
==========================================
+ Coverage   86.94%   89.42%   +2.48%     
==========================================
  Files         155      155              
  Lines       11727    11738      +11     
==========================================
+ Hits        10196    10497     +301     
+ Misses       1531     1241     -290     

Flag	Coverage Δ
daemon	44.53% <23.52%> (-0.05%)	⬇️
jina	88.20% <100.00%> (+1.79%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
jina/clients/base/__init__.py	92.75% <100.00%> (+1.84%)	⬆️
jina/clients/base/grpc.py	70.21% <100.00%> (ø)
jina/clients/base/http.py	97.43% <100.00%> (ø)
jina/clients/base/websocket.py	89.65% <100.00%> (ø)
jina/logging/profile.py	98.29% <100.00%> (+0.08%)	⬆️
jina/helper.py	83.12% <0.00%> (+0.35%)	⬆️
jina/peapods/zmq/__init__.py	89.51% <0.00%> (+0.69%)	⬆️
jina/peapods/runtimes/zmq/zed.py	94.05% <0.00%> (+0.99%)	⬆️
jina/peapods/runtimes/grpc/__init__.py	87.91% <0.00%> (+1.34%)	⬆️
jina/types/message/__init__.py	87.37% <0.00%> (+1.45%)	⬆️
... and 14 more

---

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[github-actions]

Latency summary

Current PR yields:

• 🐎🐎🐎🐎 index QPS at 1474, delta to last 2 avg.: +27%
• 🐎🐎🐎🐎 query QPS at 67, delta to last 2 avg.: +29%
• 🐎🐎🐎🐎 dam extend QPS at 56014, delta to last 2 avg.: +35%
• 🐎🐎🐎🐎 avg flow time within 1.0852 seconds, delta to last 2 avg.: -16%
• 🐢🐢 import jina within 0.432 seconds, delta to last 2 avg.: -10%

Breakdown

Version	Index QPS	Query QPS	DAM Extend QPS	Avg Flow Time (s)	Import Time (s)
current	1474	67	56014	1.0852	0.432
2.1.7	1220	53	43738	1.4684	0.4366
2.1.6	1096	49	38928	1.1267	0.5239

Backed by latency-tracking. Further commits will update this comment.