Add Compact version of the default themes.

[AfterRebelion]

Copy from zadam/trilium#4410

Basically, a discussion regarding #712

Description

Both Trilium default themes have huge visual margins between items. Specially between paragraphs.
In 1080p is already noticeable, however in 4K they are just too big.
This is also the impression given, if migrating from another note-taking solution, that uses more compact margins.

Comparison

This is a comparison, on how many 1 line paragraphs can be shown on different screen sizes.

1080p

• Logseq - Default White theme: 30
• Trilium - Default White theme: 24
• Trilium - Bear White theme: 34

4K

• Logseq - Default White theme: 40
• Trilium - Default White theme: 31
• Trilium - Bear White theme: 46

Image comparison

Examples both using default Logseq, and default Trilium.

Request

Create a compact version of default themes.
Current default can remain as-is, this is a request to have them as additional themes from were to chose from.

Example naming:

• Light
• Light-Compact
• Dark
• Dark-Compact

Workarounds

There are already some custom themes, like https://github.com/AllanZyne/trilium-bear-theme/ that already reduce the margins drastically, while retaining readability.
An official compact theme would be nice, as a middle ground between this theme, and the current default one.