Rationale: expose and promote descriptor wallets in more places; make cli tool more consistent with createwallet rpc.
Add -descriptors parameter which is off by default. When specified it will create a new descriptors wallet with sqlite backend, which is consistent with createwallet rpc.
This PR is based on a suggestion from ryanofsky #19137 (review)
Example:
 0$ ./src/bitcoin-wallet  -wallet=fewty -descriptors create
 1Topping up keypool...
 2Wallet info
 3===========
 4Name: fewty
 5Format: sqlite
 6Descriptors: yes
 7Encrypted: no
 8HD (hd seed available): yes
 9Keypool Size: 6000
10Transactions: 0
11Address Book: 0
 0$ ./src/bitcoin-wallet  -wallet=fewty create
 1Topping up keypool...
 2Wallet info
 3===========
 4Name: fewty
 5Format: bdb
 6Descriptors: no
 7Encrypted: no
 8HD (hd seed available): yes
 9Keypool Size: 2000
10Transactions: 0
11Address Book: 0