bug(#3696): skip UTs

[maxonfjvipon]

Closes: #3696

[yegor256]

@maxonfjvipon there is skipTests parameter in Maven: https://maven.apache.org/plugins-archives/maven-surefire-plugin-2.12.4/examples/skipping-test.html it's not suitable?

[maxonfjvipon]

@yegor256 skipTests skips all tests by maven-surefire-plugin and maven-failsafe-plugin except integration ones by maven-invoker-plugin.

Custom skipITs was skipping integration tests by maven-invoker-plugin, now in EO it also skips tests that end with *IT by maven-failsafe-plugin. So it skips all the integration tests.

I added one more custom skipUTs flag that skips just simple unit tests, but does not touch integration tests by maven-failsafe-plugin and maven-invoker-plugin.

So now we have:

1. mvn build that runs only unit tests without integration ones
2. qulice build that runs only qulice without any tests
3. integration bulid that runs only integration tests by maven-failsafe-plugin and maven-invoker-plugin

[maxonfjvipon]

@yegor256 please check

[yegor256]

@maxonfjvipon nice, thanks!