Allow --output-annotation-tbl as singular output

Hi Ivan, I sometimes run nextclade just to get the tbl file output: ``` nextclade run -r sequence.fasta -m sequence.gff3 --output-annotation-tbl output.tbl input.fasta ``` But this produces this: ``` 0: When deducing output filenames 1: No output flags provided. At least one of the following flags is required: --output-all --output-fasta --output-ndjson --output-json --output-csv --output-tsv --output-tree --output-translations ``` Is it possible to have the other outputs included in the above list? Very minor, feel free to close as not planned. Thanks, Ammar