Add hovers over task ids in code

[olbrich]

The Atlassian and Github integrations currently show a helpful hover when you mouse over an issue number mentioned in code, this would be very helpful for this extension as well.

see https://bitbucket.org/atlassianlabs/atlascode/src/main/src/views/jira/issueHoverProvider.ts

It may be necessary to use the CU-xxxxx format to refer to issues.

[Edsol]

It's a good features that I like to include in extension. Is necessary to use the CU id but I don't use in the current code, I will implement it soon.