Improve callback registry

[fgmacedo]

• chore: 15% faster setup with attr by name comparison
• refac: Renaming callbacks methods
• refac: Renaming callbacks to specs when refering to metadata
• refac: Removing resolver_factory

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (b18ea56) to head (2f7065e). Report is 35 commits behind head on develop.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #442 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 20 20 Lines 1236 1283 +47 Branches 180 192 +12 ========================================= + Hits 1236 1283 +47 ``` | [Flag](https://app.codecov.io/gh/fgmacedo/python-statemachine/pull/442/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Fernando+Macedo) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/fgmacedo/python-statemachine/pull/442/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Fernando+Macedo) | `100.00% <100.00%> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Fernando+Macedo#carryforward-flags-in-the-pull-request-comment) to find out more.

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[sonarcloud[bot]]

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud