82b6f89 [style] Small style improvements to DNS parameters (Amiti Uttarwar)
4c89e24 [test] Test the delay before querying DNS seeds (Amiti Uttarwar)
6395c8e [test] Test the interactions between -forcednsseed and -dnsseed (Amiti Uttarwar)
6f6b7df [init] Disallow starting up with conflicting paramters for -dnsseed and -forcednsseed (Amiti Uttarwar)
26d0ffe [test] Test -forcednsseed causes querying DNS seeds (Amiti Uttarwar)
3585145 [test] Test the interactions between -connect and -dnsseed (Amiti Uttarwar)
75c05af [test] Test logic to query DNS seeds with block-relay-only connections (Amiti Uttarwar)
9c08719 [test] Introduce test logic to query DNS seeds (Amiti Uttarwar)

Pull request description:

  This PR adds a DNS seed to the regtest chain params to enable testing the DNS seed querying logic of `CConnman::ThreadDNSAddressSeed` and relevant startup parameters. Adds coverage for the changes in bitcoin#22013 (and then some).

  The main behavioral change to bitcoind is that this PR disallows starting up with conflicting parameters for `-dnsseed` and `-forcednsseed`.

  The tests include:
  * parameter interactions of different combinations of `-connect`, `-dnsseed` and `-forcednsseed`
  * the delay before querying DNS seeds depending on how many addresses are in the addrman
  * the behavior of `-forcednsseed`
  * skipping DNS querying if we have outbound full relay connections & not block-relay-only connections

  Huge props to mzumsande for identifying the timing technique for testing successful connections before running `ThreadDNSAddressSeed` 🙌🏽

ACKs for top commit:
  mzumsande:
    ACK 82b6f89
  jnewbery:
    reACK 82b6f89

Tree-SHA512: 9f0c29bfbf99426727e79c0a25606ae09deab91a92e3c5cee7f84c3ca7503a8ac9ab85a85c51841d40b164ef8c991326070f0b2f41d075fb7985df26f6e95d6d