[REF] *: improve app icons, add SVG version

- Uniform colors and design
- Replace duplicated icons (eg. mrp_maintenance / maintenance)
- Improve misleading icons (eg. sale_subscription)
- Add icons for new apps

Add SVG versions to lossless future editing and print/marketing use.

See https://github.com/odoo/odoo/commit/1d9208c4fa92d00090b37b8e5dbed48087a7f52f

task-54681

static/description/icon.svg

@@ -0,0 +1 @@
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