Improve usability of HTML report template edit dialog

[syncro]

When user clicks on band name inside band's edit field, the band is not selected and band columns are not displayed on the right that may puzzle. Currently, to select band user have to click outside field but inside it's area that may feed tricky and unclear.

Suggested solutions:

1. Click on band edit field selects band and columns are displayed as expected
2. Add edit button that enables current behaviour only after it got clicked otherwise click always selects the band without focusing textfield edit