misc: builder: env var for managing rcmgr

[magik6k]

Also disable it by default for now, until we can figure out what's broken (also disabling by default means that people will not set the envvar to disable rcmgr and keep it after we've fixed issues)

[codecov]

Codecov Report

Merging #8282 (557c381) into master (326a9b6) will increase coverage by 5.55%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #8282      +/-   ##
==========================================
+ Coverage   34.91%   40.47%   +5.55%     
==========================================
  Files         670      675       +5     
  Lines       73299    73527     +228     
==========================================
+ Hits        25595    29758    +4163     
+ Misses      42896    38544    -4352     
- Partials     4808     5225     +417     

Impacted Files	Coverage Δ
node/builder.go	76.47% <ø> (ø)
storage/wdpost_sched.go	75.49% <0.00%> (-5.89%)	⬇️
chain/exchange/client.go	49.15% <0.00%> (-4.67%)	⬇️
miner/miner.go	56.39% <0.00%> (-1.64%)	⬇️
chain/events/observer.go	71.64% <0.00%> (-1.50%)	⬇️
extern/sector-storage/sched.go	84.77% <0.00%> (-0.83%)	⬇️
itests/kit/blockminer.go	69.61% <0.00%> (-0.56%)	⬇️
chain/actors/builtin/miner/v7.go	52.90% <0.00%> (-0.31%)	⬇️
markets/dagstore/mocks/mock_lotus_accessor.go	80.48% <0.00%> (ø)
lib/nullreader/reader.go	0.00% <0.00%> (ø)
... and 140 more

[vyzo]

that wont disable it but rather use the default.

You need to pass network.NullResourceManager to disable it.

[jennijuju]

@vyzo lmao request change!!! thank you for reviewing 🟦

[vyzo]

#8318 does it properly.