core: initialize store at manager build

[ndr-brt]

Follow up of #690 .
Since we decided to change the lock implementation as decided in #690, and given that there was a test that persisted to fail on github action (but it passed on my machine) I decided to extract the only feature it remained in that PR

What brings

Currently, on the managers (TransferProcess and ContractNegotiation) the store object is injected on the "start" method invocation. Since there are no reasons to do that, I added a store method on the builders and make it as a mandatory field on the managers.

[codecov-commenter]

Codecov Report

Merging #710 (b911a18) into main (1f62003) will increase coverage by 0.00%.
The diff coverage is 60.00%.

@@            Coverage Diff            @@
##               main     #710   +/-   ##
=========================================
  Coverage     56.37%   56.37%           
  Complexity     2088     2088           
=========================================
  Files           585      585           
  Lines         13012    13021    +9     
  Branches        925      925           
=========================================
+ Hits           7335     7341    +6     
- Misses         5255     5258    +3     
  Partials        422      422           

Impacted Files	Coverage Δ
...ceconnector/contract/ContractServiceExtension.java	0.00% <0.00%> (ø)
...connector/transfer/core/CoreTransferExtension.java	0.00% <0.00%> (ø)
...iation/ConsumerContractNegotiationManagerImpl.java	60.97% <100.00%> (+0.27%)	⬆️
...iation/ProviderContractNegotiationManagerImpl.java	64.03% <100.00%> (+0.28%)	⬆️
...sfer/core/transfer/TransferProcessManagerImpl.java	51.64% <100.00%> (+0.32%)	⬆️

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