Add delay between hovering on member and opening tooltip

#### Purpose

During fast scroll in long list of members we see tooltip for every member. The task is not showing tooltip during fast scroll. Idea of this PR to add delay between hovering on member and showing tooltip.

#### Modifications

Created additional timer. On `Tick` of timer tooltip is opened.

#### Additional references

[MAGN-5514](http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-5514).

#### Reviewers

@ramramps, please, take a look.

@Benglin, FYI.