Add option to append labels instead of overwrite

[peterjaap]

 ~/development/workspace/elgentos/hypernode-api-cli   main ±  ./hypernode-api-cli brancher:update abcm2-ephn1i49h --label="test6=test6"                
Brancher node update for abcm2-ephn1i49h requested
 ~/development/workspace/elgentos/hypernode-api-cli   main ±  ./hypernode-api-cli brancher:list abcm2                                                  
+-------+-----------------+------+----------------------------------+---------------+----------+--------------+-------------+
| Id    | Name            | Cost | Created                          | Ip            | End_time | Elapsed_time | Labels      |
+-------+-----------------+------+----------------------------------+---------------+----------+--------------+-------------+
| 16031 | abcm2-ephn1i49h | 1529 | 2023-04-03T19:27:43.654370+02:00 | 83.217.94.168 |          | 91693        | test6=test6 |
+-------+-----------------+------+----------------------------------+---------------+----------+--------------+-------------+
 ~/development/workspace/elgentos/hypernode-api-cli   main ±  ./hypernode-api-cli brancher:update abcm2-ephn1i49h --label="test5=test5" --append-labels
Brancher node update for abcm2-ephn1i49h requested
 ~/development/workspace/elgentos/hypernode-api-cli   main ±  ./hypernode-api-cli brancher:update abcm2-ephn1i49h --label="test4=test4" --append-labels
Brancher node update for abcm2-ephn1i49h requested
 ~/development/workspace/elgentos/hypernode-api-cli   main ±  ./hypernode-api-cli brancher:update abcm2-ephn1i49h --label="test3=test3"  --append-labels
Brancher node update for abcm2-ephn1i49h requested
 ~/development/workspace/elgentos/hypernode-api-cli   main ±  ./hypernode-api-cli brancher:update abcm2-ephn1i49h --label="test3=test3"  --append-labels
 ✘  ~/development/workspace/elgentos/hypernode-api-cli   main ±  ./hypernode-api-cli brancher:list abcm2                                                   
+-------+-----------------+------+----------------------------------+---------------+----------+--------------+-------------+
| Id    | Name            | Cost | Created                          | Ip            | End_time | Elapsed_time | Labels      |
+-------+-----------------+------+----------------------------------+---------------+----------+--------------+-------------+
| 16031 | abcm2-ephn1i49h | 1529 | 2023-04-03T19:27:43.654370+02:00 | 83.217.94.168 |          | 91708        | test3=test3 |
|       |                 |      |                                  |               |          |              | test4=test4 |
|       |                 |      |                                  |               |          |              | test5=test5 |
|       |                 |      |                                  |               |          |              | test6=test6 |
+-------+-----------------+------+----------------------------------+---------------+----------+--------------+-------------+

[tdgroot]

LGTM! I like the approach you took with http_build_query 😄. Gonna merge, add a test for this and then release.

[peterjaap]

@tdgroot credit for the http_build_query trick goes to our new best friend GPT-4 😄