feat!: beacon configuration for Capella/Deneb upgrade (#7)

```
CAPELLA_FORK_EPOCH = (shanghaiTime - genesis_time) / SECONDS_PER_SLOT / SLOTS_PER_EPOCH
DENEB_FORK_EPOCH = (cancunTime - genesis_time) / SECONDS_PER_SLOT / SLOTS_PER_EPOCH
```

networks/mainnet/config.yml

@@ -38,11 +38,11 @@ BELLATRIX_FORK_VERSION: 0x20000091
 # Capella
 # Transition: 60 minutes * 60 seconds / 6 seconds per slot / 8 slots per epoch (=75 epochs)
 # Transition + (28 minutes * 60 seconds / 6 seconds per slot / 8 slots per epoch (= 35 epochs))
-CAPELLA_FORK_EPOCH: 18446744073709551615
+CAPELLA_FORK_EPOCH: 503609
 CAPELLA_FORK_VERSION: 0x20000092
 
 # # Deneb
-DENEB_FORK_EPOCH: 18446744073709551615
+DENEB_FORK_EPOCH: 503609
 DENEB_FORK_VERSION: 0x20000093
 
 # Future forks
@@ -81,12 +81,15 @@ ETH1_FOLLOW_DISTANCE: 32
 
 # Execution
 # ---------------------------------------------------------------
-# MAX_WITHDRAWALS_PER_PAYLOAD: 17  # temporarily disabled
+# Maximum number of withdrawals included in a block
+# Use the default value of 2**4 (= 16)
+MAX_WITHDRAWALS_PER_PAYLOAD: 16
 
 # Withdrawals
 # ---------------------------------------------------------------
-# 2**5 (= 32) validators
-# MAX_VALIDATORS_PER_WITHDRAWALS_SWEEP: 32  # temporarily disabled
+# Maximum number of validators a node will search through to find sufficient withdrawals to include
+# 2**10 (= 1024) validators
+MAX_VALIDATORS_PER_WITHDRAWALS_SWEEP: 1024
 
 # Validator cycle
 # ---------------------------------------------------------------
@@ -107,8 +110,9 @@ DEPOSIT_CONTRACT_ADDRESS: 0x17BbE91c315Bf14f38F6D35052a827cadfFe184e
 # 1000 * 10**9 (= 1,000,000,000,000) Gwei
 MIN_DEPOSIT_AMOUNT: 1000000000000
 # 35000 * 10**9 (= 35,000,000,000,000) Gwei
-# Relevant after Electra fork
-# MIN_ACTIVATION_BALANCE: 35000000000000
+# Mainly for Electra, but since Deneb, Prysm uses MIN_ACTIVATION_BALANCE 
+# to determine if a validator is active
+MIN_ACTIVATION_BALANCE: 35000000000000
 # 35000 * 10**9 (= 35,000,000,000,000) Gwei
 MAX_EFFECTIVE_BALANCE: 35000000000000
 # 1000 * 10**9 (= 1,000,000,000,000) Gwei