Refactor OptionalDouble and OptionalLong

[iselo]

This PR eliminates if-statements and additional presence variable, reduces bytecode size and code execution passthrough.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (0fa0e9e) 100.00% compared to head (3ef21c2) 100.00%.

Additional details and impacted files

@@             Coverage Diff             @@
##              master       #13   +/-   ##
===========================================
  Coverage     100.00%   100.00%           
- Complexity        45        83   +38     
===========================================
  Files              2         4    +2     
  Lines             93       171   +78     
  Branches           3         6    +3     
===========================================
+ Hits              93       171   +78     

Files Changed	Coverage Δ
lib/src/main/java/co/raccoons/meeko/Optional.java	100.00% <ø> (ø)
...b/src/main/java/co/raccoons/meeko/OptionalInt.java	100.00% <ø> (ø)
...rc/main/java/co/raccoons/meeko/OptionalDouble.java	100.00% <100.00%> (ø)
.../src/main/java/co/raccoons/meeko/OptionalLong.java	100.00% <100.00%> (ø)

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[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication