A new config API is introduced, and ~all of the codebase is adapted to it.
The old API is kept but mainly only for dynamic usage where its extra flexibility is needed.
Using examples, the old config API looked this:
```
>>> config.get("request_expiry", 86400)
604800
>>> config.set_key("request_expiry", 86400)
>>>
```
The new config API instead:
```
>>> config.WALLET_PAYREQ_EXPIRY_SECONDS
604800
>>> config.WALLET_PAYREQ_EXPIRY_SECONDS = 86400
>>>
```
The old API operated on arbitrary string keys, the new one uses
a static ~enum-like list of variables.
With the new API:
- there is a single centralised list of config variables, as opposed to
these being scattered all over
- no more duplication of default values (in the getters)
- there is now some (minimal for now) type-validation/conversion for
the config values
closes https://github.com/spesmilo/electrum/pull/5640
closes https://github.com/spesmilo/electrum/pull/5649
Note: there is yet a third API added here, for certain niche/abstract use-cases,
where we need a reference to the config variable itself.
It should only be used when needed:
```
>>> var = config.cv.WALLET_PAYREQ_EXPIRY_SECONDS
>>> var
<ConfigVarWithConfig key='request_expiry'>
>>> var.get()
604800
>>> var.set(3600)
>>> var.get_default_value()
86400
>>> var.is_set()
True
>>> var.is_modifiable()
True
```
B023 Function definition does not bind loop variable 'already_selected_buckets_value_sum'
in keepkey/qt.py, looks like this was an actual bug
(fixed in trezor plugin already: 52a4810752 )
- Rename bump_fee "methods" to "strategies".
- Refactor strategies so that bump_fee can use any subset of them in any permutation.
- Adds a new strategy which decreases the payment outputs (instead of change).
Calculate the effective value of buckets, and filter <0 out.
Note that the filtering is done on the buckets, not per-coin.
This should better preserve the user's privacy in certain cases.
When the user "sends Max", as before, all UTXOs are selected,
even if they are not economical to spend.
see #5433
existing code was n^2 in number of UTXOs
this is now mostly linear
(linear if shortcut is hit; otherwise in rare cases still quadratic)
tested using wallet with 800 UTXOs, most of which were needed to make payment
coinchooser.make_tx() went from 18 sec to 0.8 sec
