142e2da net: add I2P seeds to chainparamsseeds (Jon Atack)
e01f173 contrib: add a few I2P seed nodes (Jon Atack)
ea269c7 contrib: parse I2P addresses in generate-seeds.py (Jon Atack)

Pull request description:

  Follow-up to #21560 that updated the fixed seeds infra for BIP155 addresses and then added Tor v3 ones:

  - Update contrib/generate-seeds.py to parse I2P addresses

  - Add a few I2P nodes to contrib/seeds/nodes_main.txt

  - Run generate-seeds.py and add the I2P seeds to chainparamsseeds.h

  Reviewers, see contrib/seeds/README.md for more info and feel free to use the following CLI one-liner to check for and propose additional seeds for contrib/seeds/nodes_main.txt. You can also see how many I2P peers your node knows with cli -addrinfo.

  ```rake
  bitcoin-cli getnodeaddresses 0 | jq '.[] | (select(.address | contains(".b32.i2p"))) | .address' | sort
  ```

  I verified the I2P addresses are correctly BIP155-serialized/deserialized by building with all seeds removed from chainparamsseeds.h except those added here, restarting with `-datadir=newdir -dnsseed=0` and running rpc ` getnodeaddresses 0` that initially returns only the new I2P addresses.

ACKs for top commit:
  laanwj:
    ACK 142e2da
  vasild:
    ACK 142e2da

Tree-SHA512: 040576012d5f1f034e2bd566ad654a6fdfd8ff7f6b12fa40c9fda1e948ebf8417fcea64cfc14938a41439370aa4669bab3e97274f9d4f9a6906fa9520afa9cf8

6fe0516 contrib: add torv3 seed nodes for testnet, drop v2 ones (Jon Atack)

Pull request description:

  Replace the ancient (2015) Tor V2 hardcoded seeds with new Tor V3 ones. This needs to be done before 0.22 to make sure onion-only testnet nodes can still connect to the network. Continues #21560.

  Ways to test:
  - Re-generate ` src/chainparamsseeds.h` with `cd contrib/seeds && python3 generate-seeds.py . > ../../src/chainparamsseeds.h`, check if git tree stays the same.
  - Create a new testnet node with `bitcoind -testnet -onlynet=onion -proxy=127.0.0.1:9050` (or delete `~/.bitcoin/testnet3/peers.dat`), check if it is able to connect to the network and get blocks.
  - Check if the addresses are connectable for ex.:
  ```python3
  #!/usr/bin/env python3
  import subprocess
  with open('contrib/seeds/nodes_test.txt') as f:
      for line in (line for line in (line.rstrip().split('#', 1)[0] for line in f) if line):
          subprocess.call(["nc", "-v", "-x", "127.0.0.1:9050", "-z"] + line.split(':'))
  ```

  Thanks to jonatack for providing the list.

ACKs for top commit:
  jonatack:
    ACK 6fe0516

Tree-SHA512: 61bfdb44dfab9d02b75e5cb06c089a3b1a1fe7134875e1d09166c4116e961d809aa25422fe03f068876e9423b571ecc4a0c7a7eeacba4aac3b2768717f3ee6d6

4aec935 net: Deserialize hardcoded seeds from BIP155 blob (Fuzzbawls)
a245b2f contrib: generate-seeds.py generates output in BIP155 format (Fuzzbawls)

Pull request description:

  Adapted from bitcoin#21560, this adds support for Tor v3 hardcoded seed nodes.

  Upstream PR description:

  > * Add a few hardcoded seeds for TorV3
  >   * As the bitcoin-seeder doesn't collect TorV3 addresses yet, I have extracted these from my own node using a [script](https://gist.github.com/laanwj/b3d7b01ef61ce07c2eff0a72a6b90183) and added them manually. This is intended to be a temporary stop gap until 22.0's seeds update.
  > * Change hardcoded seeds to variable length BIP155 binary format.
  >   * It is stored as a single serialized blob in a byte array, instead of pseudo-IPv6 address slots. This is more flexible and, assuming most of the list is IPv4, more compact.
  >   * Only the (networkID, addr, port) subset (CService). Services and time are construed on the fly as before.
  > * Change input format for nodes_*.txt.
  >   * Drop legacy 0xAABBCCDD format for IPv4. It is never generated by makeseeds.py.
  >   * Stop interpreting lack of port as default port, interpret it as 'no port', to accomodate I2P and other port-less protocols (not handled in this PR). An explicit port is always generated by makeseeds.py so in practice this makes no difference right now.

  Marked as WIP for now because we need more Tor v3 nodes on mainnet for this to really be of use to end users, but this is currently testable on testnet as we already have a number of Tor v3 capable nodes there (which have been added to the hardcoded seeds here)

ACKs for top commit:
  random-zebra:
    ACK 4aec935
  furszy:
    ACK 4aec935

Tree-SHA512: 5abf2faa49ca511001589d950fa95a6f4c346a391ab0b31b3137b962765dc5a5ba343aa4c7b7fa0d7be931d4ec4802d9c09ec9b5dd2ef90143d4623162da14af