Use vault accounts for fragmenter

[altafan]

This updates the fragmentation logic in order to deprecate the usage of ephemeral wallets in favour of reserved accounts of Vault domain.

Daemon

For this, the fragmenter portable interface (ports.Fragmenter) and all other relative types/interfaces have been dropped. Basically, the only thing re-used is the fragmentation logic of the original FragmentAmount() method of both fee and market fragmnenter implementations. These methods have been moved to a fragmenter_utils.go file and became internal methods of the app layer.

As already introduced, this makes use of 2 Vault reserved accounts that have been named FeeFragmenter and MarketFragmenter accounts. This has the benefit of not taking the risk of loosing funds during a fragmentation as explained in the related ticket.

Several RPCs have been added for these 2 new accounts to look similar to those defined for the Fee and Market ones:

• ListFeeFragmenterAddresses to list all external addresses derived for the account
• GetFeeFragmenterBalance to retrieve the current balance of the account
• FeeFragmenterSplitFunds to perform fragmentation and deposit funds into fee account. The original FragmentFeeFragmenterDeposits is dropped.
• WithdrawFeeFragmenter to withdraw ALL the funds owned by the account to some address

The same is done for the MarketFragmenter account.

CLI

On the CLI side, the interactive process originally done with tdex fee|market deposit --fragment is deprecated. Instead, 2 new main commands are added:

• feefragmenter to manage the fee fragmenter account
• marketfragmenter to manage the market fragmenter account

Both commands have the following subcommands:

• deposit [--num_of_addresses] to retrieve address where to send funds
• addresses to list all deposit (external) addresses
• balance to see the current balance of the account
• split to perform fragmentation&deposit into fee/market account
• withdraw to send ALL the funds owned by the fragmenter to an external address

Therefore, the process is no-longer interactive. The operator needs to call at least deposit and split to perform the fragmentation of the funds.

BONUS:

• In order to use the pkg/wallet to craft the deposit or withdraw transaction of the fragmenters, it's been necessary to add the option to the UpdateTx() to subtract fees from some LBTC output that is going to be added to the transaction. This can now be done by setting the new param SubtractFees, which is mutually exclusive to WantChangeForFees, which instead instructs to either subtract the fees from a change LBTC out, or to add one by making a new coinselction.
• Rename the internal methods sendToMany and sendToManyFeeAccount of the app layer to sendToManyWIthFeeTopup and sendToManyWithoutFeeTopup to better understand their purpose.
• This fixes some typos in the operator.proto file

Closes #495.

Please @tiero review this.

[tiero]

Just asking, Why we couldn't keep the tdex fee|market deposit --fragment UX instead of adding specific commands? @altafan

[altafan]

Since FeeFragmenter and MarketFragmenter became accounts similar to the Fee and Market ones, I thought they needed similar RPCs for consistency. Like for instance to check the balance or to list of all derivated deposit addresses.

At this point, the CLI would have been enriched with new commands anyways, so I decided to deprecate the interactive process of the fee/market account commands.