Started virtual scroll in extension

Related to passit#90 (closed)

What problem does this solve

The web ext popup is slow - taking between 500ms and 1.5 seconds to load depending on number of secrets. This attempts to improve performance. For an account with 300 secrets I get load times that are 50%-70% faster.

Implementation

Angular 7's virtual scrolling solves increases performance because only visible secrets are rendered.

Problems to solve

• Height is wrong Please check my logic for combining lists
• Minor width issue when expanding a secret Changed width to 100% and it works