Add minimal build docker image and reproducible bash script

[matevz]

Fixes #2596

[codecov[bot]]

Codecov Report

Merging #2980 into master will decrease coverage by 0.06%. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2980      +/-   ##
==========================================
- Coverage   68.74%   68.68%   -0.07%     
==========================================
  Files         360      360              
  Lines       35285    35285              
==========================================
- Hits        24258    24236      -22     
- Misses       7922     7972      +50     
+ Partials     3105     3077      -28     

Impacted Files	Coverage Δ
go/consensus/tendermint/apps/scheduler/query.go	71.05% <0.00%> (-7.90%)	:arrow_down:
go/consensus/tendermint/apps/staking/query.go	49.09% <0.00%> (-7.28%)	:arrow_down:
go/registry/api/grpc.go	33.33% <0.00%> (-6.73%)	:arrow_down:
go/common/cbor/codec.go	78.37% <0.00%> (-5.41%)	:arrow_down:
go/common/grpc/proxy/proxy.go	62.60% <0.00%> (-5.22%)	:arrow_down:
go/staking/api/grpc.go	53.19% <0.00%> (-4.66%)	:arrow_down:
go/consensus/tendermint/abci/mux.go	70.27% <0.00%> (-3.46%)	:arrow_down:
go/consensus/tendermint/staking/staking.go	67.44% <0.00%> (-2.33%)	:arrow_down:
go/consensus/tendermint/apps/roothash/roothash.go	71.71% <0.00%> (-1.77%)	:arrow_down:
go/runtime/client/watcher.go	73.84% <0.00%> (-1.54%)	:arrow_down:
... and 31 more

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