Avoid methods relying on default locale or charset

[sebastian-nagel]

Methods relying on the System's default locale or character set may cause unexpected results:

jshell> import org.archive.url.WaybackURLKeyMaker;

jshell> WaybackURLKeyMaker surtKeyMaker = new WaybackURLKeyMaker(true);
surtKeyMaker ==> org.archive.url.WaybackURLKeyMaker@4534b60d

jshell> surtKeyMaker.makeKey("https://SITE.ORG/")
$3 ==> "org,site)/"

jshell> Locale.setDefault(Locale.of("tr", "TR"))

jshell> surtKeyMaker.makeKey("https://SITE.ORG/")
$5 ==> "org,s%c4%b1te)/"

For code bundle in a software library, it is good practice to avoid these methods and use the ROOT locale, see
https://blog.thetaphi.de/2012/07/default-locales-default-charsets-and.html.

A PR is underway adding Uwe Schindler's "forbidden APIs" Maven plugin and fixing all occurrences of methods relying on default locale or charset.