Transfer SmartLengthInputFilter license to Tusky (#1384)

* Transfer SmartLengthInputFilter in-header license

Transfer license for file "SmartLengthInputFilter.java" from me (Diego Rossi) to Tusky and therefore also change it from the original Apache 2.0 to currently GPLv3. This was a mistake that has been sitting around for way too long.

* Rewrite SmartLengthInputFilter from Java to Kotlin

This has been done by hand, without the custom copy-paste tool.

* Fix bad references in Java files using SmartLengthInputFilter features

* Shorten code in Java classes referencing SmartLengthInputFilter instance

* Refactor SmartLengthInputFilter from class to singleton Kotlin object

* Move hasBadRatio to become a toplevel function

* Patch up all the files affected by SmartLengthInputFilter changes

* Length in SmartLengthInputFilter is const 500, simplify code accordingly

* More meaningful name for toplevel function for checking trimming ability

* Add missing license header

app/src/main/java/com/keylesspalace/tusky/util/ViewDataUtils.java

@@ -58,10 +58,7 @@ public final class ViewDataUtils {
                 .setApplication(visibleStatus.getApplication())
                 .setStatusEmojis(visibleStatus.getEmojis())
                 .setAccountEmojis(visibleStatus.getAccount().getEmojis())
-                .setCollapsible(!SmartLengthInputFilter.hasBadRatio(
-                        visibleStatus.getContent(),
-                        SmartLengthInputFilter.LENGTH_DEFAULT
-                ))
+                .setCollapsible(!SmartLengthInputFilterKt.shouldTrimStatus(visibleStatus.getContent()))
                 .setCollapsed(true)
                 .setPoll(visibleStatus.getPoll())
                 .setCard(visibleStatus.getCard())