First time use we may help user with "Got It" tooltip

[Vassiliy-Kudryashov]

Description

First time the plugin shown a hint, "Got it message" to promote the plugin and especially its actual shortcut

Fixes #157

Type of Change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Manual Scenario

1. Start IDE with plugin and clean config (to get the config clean in terms of this issue you may delete a line <property name="UTBot.GotItMessageWasShown" value="true" /> in config/options/other.xml

2. Check if the message appears after some initial activity (loading/indexing etc.), don't press 'Got it' button.

3. Restart IDE, the message has to appear again, now press 'Got it button'

4. Restart IDE, ensure the message doesn't appear again.

Checklist (remove irrelevant options):

• The change followed the style guidelines of the UTBot project
• Self-review of the code is passed
• The change contains enough commentaries, particularly in hard-to-understand areas
• New documentation is provided or existed one is altered
• No new warnings
• Tests that prove my change is effective
• All tests pass locally with my changes

Visual proof

[denis-fokin]

Please, add a screenshot. The screenshot will help to evaluate correctness of the behavior in future