BC-5178 - Improve icon references

[NFriedo]

Short Description

Provide a clearly defined set of icons under the path "@icons/material".
The import of icons from that path is enforced by a custom linter rule.

Links to Ticket and related Pull-Requests

BC-5178

Changes

• add custom linter rule for material icon imports
• add local plugin for eslint: eslint-plugin-schulcloud in lib directory
• remove prefix "mdiCustom" for custom icons
• import icons instead of using string aliases for material icons (replace "$mdi...")

Data-security

Deployment

New Repos, NPM packages or vendor scripts

Screenshots of UI changes

Checklist before merging

• QA: In addition to review, the code has been manually tested (if manual testing is possible)
• PO: Any deviation from requirements was agreed with Product-Owner / ticket author / support-team
• DEV: Every new component is implemented having accessibility in mind (e.g. aria-label, role property)

Notice: Please keep this Pull-Request as a Draft (or add WIP label), until it is ready to be reviewed

[sonarcloud]

Quality Gate passed

Issues
0 New issues
2 Accepted issues

Measures
0 Security Hotspots
85.6% Coverage on New Code
2.5% Duplication on New Code

See analysis details on SonarCloud