await driver methods

[ssxv]

For USB connected printers,

• await driver.getPrinter in isPrinterConnected method.
• await driver.getPrinters in getPrinterName
• update printer retrieval in isPrinterConnected and execute methods

[andidev]

@ssxv I was about to create similar pr. I would suggest to add following to this PR:
ssxv/node-thermal-printer@master...andidev:node-thermal-printer:master

current references in docs to node-printer libs are just too outdated and does not work with latest javascript so worth changing those as well.

@Klemen1337 what do you say?

[andidev]

@ssxv I think the Interface class

node-thermal-printer/lib/interfaces/interface.js

Line 2 in 8654d08

getPrinterName () {

should also be changed to async.
Seems like it’s only used for the printer driver implementation so should be safe.
Though @Klemen1337 this is a smaller breaking change since now it will return a promise, so probably worth mentioning in the release notes.