[ADD] Advanced gas for BTC

[realpaaao]

That the user has more flexibility and less stuck txs in the mempool, please add a advanced gas setting page according to figma:

Where
LOW = 0.75 * current rate
Normal = 1 * current rate
FAST = 2.5 * current rate

When selecting those rates please display in the text field and also let the text field be editable that the user can select its on rate.

also apply CEILING to those values. That the numbers get rounded up

[realpaaao]

QA done.