feat: add logo and favicons #6

Job	Run time
Coverage report / test-coverage-internal	1m 58s
Check NN version / macos-latest (R 4.3.1, 2023-10-25)	1m 44s
Check current version / macos-latest (release)	1m 41s
Check NN version / macos-latest (R 4.4.1, 2024-08-06)	1m 24s
Check current version / windows-latest (release)	2m 13s
Check NN version / windows-latest (R 4.3.1, 2023-10-25)	4m 55s
Check current version / ubuntu-latest (devel)	2m 32s
Check NN version / windows-latest (R 4.4.1, 2024-08-06)	1m 45s
Check current version / ubuntu-latest (release)	2m 18s
Check NN version / ubuntu-latest (R 4.3.1, 2023-10-25)	6m 19s
Check current version / ubuntu-latest (oldrel-1)	1m 43s
Check NN version / ubuntu-latest (R 4.4.1, 2024-08-06)	5m 20s
Megalinter / MegaLinter	2m 24s
Pkgdown site / pkgdown	2m 43s
	38m 59s

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