Set MaxBlockLevels for non-mainnet networks to 250

[stasatdaglabs]

Testnet difficulty is significantly lower than mainnet's. Mainnet's MaxBlockLevel caused testnet to keep significantly more block levels than necessary in RAM, causing OoM crashes and such.

This PR makes MaxBlockLevel depend on the network, and sets it to 250 for non-mainnet networks.

[codecov]

Codecov Report

Merging #1952 (87cb4df) into dev (3f7e482) will decrease coverage by 0.00%.
The diff coverage is 90.24%.

@@            Coverage Diff             @@
##              dev    #1952      +/-   ##
==========================================
- Coverage   61.07%   61.06%   -0.01%     
==========================================
  Files         640      640              
  Lines       30025    30034       +9     
==========================================
+ Hits        18337    18341       +4     
- Misses       9088     9094       +6     
+ Partials     2600     2599       -1     

Impacted Files	Coverage Δ
domain/consensus/model/externalapi/block.go	100.00% <ø> (ø)
domain/dagconfig/params.go	89.47% <ø> (ø)
...ocesses/pruningproofmanager/pruningproofmanager.go	58.04% <60.00%> (+0.10%)	⬆️
domain/consensus/factory.go	93.59% <100.00%> (+0.05%)	⬆️
...processes/blockparentbuilder/blockparentbuilder.go	77.47% <100.00%> (+0.20%)	⬆️
...nsensus/processes/blockprocessor/blockprocessor.go	100.00% <100.00%> (ø)
...cesses/blockprocessor/validate_and_insert_block.go	70.00% <100.00%> (ø)
...rocesses/blockvalidator/block_header_in_context.go	61.94% <100.00%> (ø)
...nsensus/processes/blockvalidator/blockvalidator.go	100.00% <100.00%> (ø)
.../pruning_violation_proof_of_work_and_difficulty.go	68.75% <100.00%> (ø)
... and 5 more

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