Enhance Fee Rate Logic (#1134)

* refactor: simplify variable names in fee rate fetching function

* feat: implement retry strategy for fetching fee rate from mempool.space API

* revert unrelated changes

* refactor: rename variables for clarity in fee rate fetching function

* feat: add error handling for non-success status in fee rate fetching and add hard cap

* fmt

* feat: add FeeErr enum for error handling in fee rate fetching with retry logic

* feat: add TX_SENDER_FEE_RATE_HARD_CAP configuration for transaction fee rate limits

* feat: enhance fee rate fetching by using minimum from mempool.space and Bitcoin Core RPC with hard cap enforcement

* fmt + clippy

* add TX_SENDER_FEE_RATE_HARD_CAP environment variable and configuration

* remove redundant fieds + utilise RetryConfig

* refactor: update fee rate calculation to use sat/kvB

* refactor: adjust fee rate retrieval timeout and retry configuration

* add fee rate tests with mock rpc and mempool space server

* add hard cap test + update get_fee_rate comment

* fix: Aggregator rpc related issue (#1132)

* disable forced no client verification in create_aggregator_grpc_server

* check that movetx is actually a movetx

* Update core/src/rpc/aggregator.rs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

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Co-authored-by: Ekrem BAL <mail.ekrembal@gmail.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update core/src/tx_sender/mod.rs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* fetch fee rate for signet from mempool space and rpc

* fix: remove redundant error response for connection error in tests

* fix: update documentation for fee rate fetching logic in TxSender

* remove outdated test

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Co-authored-by: Ekrem BAL <mail.ekrembal@gmail.com>
Co-authored-by: atacann <111396231+atacann@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: 4 people

.env.example

@@ -86,3 +86,4 @@ CITREA_RPC_URL=http://127.0.0.1:1234
 CITREA_LIGHT_CLIENT_PROVER_URL=http://127.0.0.1:1235
 CITREA_CHAIN_ID=5655
 BRIDGE_CONTRACT_ADDRESS=3100000000000000000000000000000000000002
+TX_SENDER_FEE_RATE_HARD_CAP=100