introduce dynamic fee types

[malteish]

FeeSettings.sol rework

What changed

The fee system has been generalized from three hardcoded fee types to a
dynamic registry. Previously, FeeSettings had TOKEN, CROWDINVESTING, and
PRIVATE_OFFER baked in as constants with fixed per-type caps (5%, 10%, 5%).
Now, fee types are registered at deployment (or later) with arbitrary names and
caps, and the contract can accommodate new product lines without an upgrade.

How fees work now:

• Each fee type is identified by a bytes32 key (e.g. keccak256("TOKEN"))
  and configured with a max cap and a default numerator at registration time.
• Custom per-token discounts and fee collector overrides work the same way as
  before, but are now keyed by (feeType, token) instead of living in
  separate mappings per type.
• Fee increases still require a 12-week delay, now enforced per fee type
  independently.
• Owner registers types and sets defaults; managers grant per-token discounts
  — same role separation as before.

What stays compatible

All existing callers (Token, Crowdinvesting, PrivateOffer contracts) continue
to work unchanged. The V1 and V2 interface functions (tokenFee,
crowdinvestingFee, privateOfferFee, and the matching feeCollector
variants) are retained as thin wrappers over the new generic logic. ERC-165
reports support for V1, V2, and the new V3 interface.

What breaks

Any tooling or scripts that call the old management functions by name will need
updating: planFeeChange(Fees), executeFeeChange(), setFeeCollectors(...),
setCustomFee(address, Fees), and the six per-type collector setters/removers
are all replaced by generic equivalents that take a bytes32 feeType as the
first argument. Events have changed accordingly.

[openzeppelin-code]

introduce dynamic fee types

Generated at commit: 4724d9a36a20a318f5853e04874b83d6e4199727

🚨 Report Summary

	Severity Level	Results
Contracts	Critical High Medium Low Note Total	2 2 0 5 28 37
Dependencies	Critical High Medium Low Note Total	0 0 0 0 0 0

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