[18.0][IMP] - css sticky table header added on mis-builder reports

[hitrosol]

No description provided.

[OCA-git-bot]

Hi @sbidoul,
some modules you are maintaining are being modified, check this out!

[dora-jurcevic]

Hello @hitrosol !
I tested on firefox and seems to be working well with the runbot demo data.
Just one comment, maybe it would be better to use the bootstrap variables for colors , like this :
background-color: var(--gray-300);

[hitrosol]

Thank you for your review and suggestions, @dora-jurcevic. I’ve implemented the changes.
I’m also planning in the next PR to freeze the left column in reports with many columns to help users maintain context.