Improve HTTP server

[vinc]

• Add root directory
• Add support for images
• Add support for index.html and index.txt files
• Add read only mode
• Add colors to logs
• Add Request and Response structs
• Handle concurrent requests with a connection pool
• Improve performance by reducing wait duration

[vinc]

Launch the server from QEMU then browse http://localhost:8080 from the host:

> dhcp
ip:  10.0.2.15/24
gw:  10.0.2.2
dns: 10.0.2.3

> httpd -r -d /var/www
HTTP Server listening on 0.0.0.0:80
10.0.2.2 - - [2022-08-21 19:21:03 +0000] "GET /" 200 876
10.0.2.2 - - [2022-08-21 19:21:04 +0000] "GET /moros.png" 200 17874
10.0.2.2 - - [2022-08-21 19:22:08 +0000] "GET /moros.bin" 404 20

[vinc]

Adding a socket pool and limiting the time spent sleeping between polls improved the concurrency and throughput of the server, especially when using a filesystem in memory (with memory format):

> siege -c 8 -r 64 -b --no-parser http://127.0.0.1:8080
** SIEGE 4.1.2
** Preparing 8 concurrent users for battle.
The server is now under siege...
HTTP/1.0 200     0.05 secs:     876 bytes ==> GET  /
HTTP/1.0 200     0.01 secs:     876 bytes ==> GET  /
HTTP/1.0 200     0.02 secs:     876 bytes ==> GET  /
HTTP/1.0 200     0.01 secs:     876 bytes ==> GET  /
HTTP/1.0 200     0.01 secs:     876 bytes ==> GET  /
...
HTTP/1.0 200     0.02 secs:     876 bytes ==> GET  /
HTTP/1.0 200     0.01 secs:     876 bytes ==> GET  /
HTTP/1.0 200     0.01 secs:     876 bytes ==> GET  /
HTTP/1.0 200     0.02 secs:     876 bytes ==> GET  /
HTTP/1.0 200     0.00 secs:     876 bytes ==> GET  /

Transactions:		         512 hits
Availability:		      100.00 %
Elapsed time:		        5.23 secs
Data transferred:	        0.43 MB
Response time:		        0.06 secs
Transaction rate:	       97.90 trans/sec
Throughput:		        0.08 MB/sec
Concurrency:		        5.45
Successful transactions:         512
Failed transactions:	           0
Longest transaction:	        1.23
Shortest transaction:	        0.01