Mark GetBundleForChannel as deprecated and trim its response.

[benluddy]

The RPC api.Registry/GetBundleForChannel is consumed only by
package-server and by declarative index conversion. Neither reads any
field other than CsvName and CsvJson. The package-server generates one
call to this RPC per channel per package per catalog and is
responsible for needlessly large CPU utilization and resident set
sizes on registry pods. Removing the additional per-request processing
and database queries that populate unused fields makes the registry
server better able to absorb the bursty load from package-server.

Before:

$ ghz -d '{"pkgName":"mongodb-enterprise","channelName":"stable"}' --insecure --concurrency=50 --duration=10s --call=api.Registry/GetBundleForChannel localhost:50051; top -b -n1 | grep opm

Summary:
  Count:	14677
  Total:	10.00 s
  Slowest:	164.41 ms
  Fastest:	2.81 ms
  Average:	34.00 ms
  Requests/sec:	1467.34

Response time histogram:
  2.808   [1]    |
  18.968  [3046] |∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎
  35.128  [5288] |∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎
  51.289  [3780] |∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎
  67.449  [1771] |∎∎∎∎∎∎∎∎∎∎∎∎∎
  83.609  [553]  |∎∎∎∎
  99.769  [143]  |∎
  115.929 [38]   |
  132.089 [5]    |
  148.249 [1]    |
  164.409 [2]    |

Latency distribution:
  10 % in 9.80 ms 
  25 % in 21.44 ms 
  50 % in 31.29 ms 
  75 % in 45.75 ms 
  90 % in 59.09 ms 
  95 % in 67.55 ms 
  99 % in 86.49 ms 

Status code distribution:
  [OK]            14628 responses   
  [Unavailable]   49 responses      

Error distribution:
  [49]   rpc error: code = Unavailable desc = transport is closing   

 518843 user  20   0 6576700 128252  30376 S  12.5   0.4   2:56.35 opm

After:

$ ghz -d '{"pkgName":"mongodb-enterprise","channelName":"stable"}' --insecure --concurrency=50 --duration=10s --call=api.Registry/GetBundleForChannel localhost:50051; top -b -n1 | grep opm

Summary:
  Count:	80470
  Total:	10.01 s
  Slowest:	47.58 ms
  Fastest:	0.18 ms
  Average:	6.16 ms
  Requests/sec:	8040.87

Response time histogram:
  0.185  [1]     |
  4.924  [54268] |∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎∎
  9.663  [3217]  |∎∎
  14.402 [4495]  |∎∎∎
  19.141 [10180] |∎∎∎∎∎∎∎∎
  23.880 [6790]  |∎∎∎∎∎
  28.619 [1223]  |∎
  33.358 [198]   |
  38.097 [37]    |
  42.836 [11]    |
  47.575 [1]     |

Latency distribution:
  10 % in 0.33 ms 
  25 % in 0.49 ms 
  50 % in 1.31 ms 
  75 % in 13.15 ms 
  90 % in 19.23 ms 
  95 % in 21.35 ms 
  99 % in 25.41 ms 

Status code distribution:
  [OK]            80421 responses   
  [Unavailable]   49 responses      

Error distribution:
  [49]   rpc error: code = Unavailable desc = transport is closing   

 518256 user  20   0 5986076  82300  30704 S   6.2   0.3   2:52.65 opm

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: benluddy

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[codecov]

Codecov Report

Merging #769 (021ba4b) into master (9bf77cf) will decrease coverage by 0.03%.
The diff coverage is 86.66%.

@@            Coverage Diff             @@
##           master     #769      +/-   ##
==========================================
- Coverage   50.41%   50.37%   -0.04%     
==========================================
  Files         102      102              
  Lines        8725     8702      -23     
==========================================
- Hits         4399     4384      -15     
+ Misses       3473     3469       -4     
+ Partials      853      849       -4     

Impacted Files	Coverage Δ
pkg/sqlite/query.go	64.61% <86.66%> (-0.02%)	⬇️
pkg/lib/bundle/supported_resources.go	100.00% <0.00%> (ø)

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[timflannagan]

TIL sql.Named is a thing 👍

[kevinrizza]

/lgtm