docker: add profile support and improved endpoint access.

[winder]

Summary

Final feature from #5197

These changes make the docker container easier to use without providing a config.json file, and make the behavior more expected when a config.json file is provided.

1. Move the endpoint address setting down. This ensures that the API is available at port 8080. Users who override the config.json file via /etc/algorand/config.json or the PROFILE environment variable would be likely to miss this option and be unable to access the REST API.
2. New PROFILE environment variable. When set algocfg is used to initialize the config.json file.

Test Plan

Manual testing. By mounting a data directory in different scenarios observe that the config.json file is set as expected.

EndpointAddress Override

Mount a config.json file

~$ cat algod_config.json
{
	"CatchupParallelBlocks": 32,
	"MaxAcctLookback": 64,
	"EnableFollowMode": true
}
~$ docker run --rm -it \
    -p 4000:8080 \
    --name algod-test-run \
    -e TOKEN=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa \
    -v (pwd)/algod_config.json:/etc/algorand/config.json \
    -v (pwd)/docker_data_dir:/algod/data \
    wwinder/algod:latest

Observe that the EndpointAddress is added to the other settings:

~$ cat docker_data_dir/config.json
{
	"EndpointAddress": "0.0.0.0:8080",
	"CatchupParallelBlocks": 32,
	"MaxAcctLookback": 64,
	"EnableFollowMode": true
}

algocfg profile

Add a PROFILE environment variable

~$ docker run --rm -it \
    -p 4000:8080 \
    --name algod-test-run \
    -e TOKEN=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa \
    -e PROFILE=relay \
    -v (pwd)/docker_data_dir:/algod/data \
    wwinder/algod:latest

Observe that the profile settings, and EndpointAddress setting are properly set:

~$ cat docker_data_dir/config.json
{
	"GossipFanout": 0,
	"IncomingConnectionsLimit": 0,
	"EndpointAddress": "0.0.0.0:8080",
	"DNSBootstrapID": "",
	"EnableProfiler": true,
	"EnableRuntimeMetrics": true,
	"DisableNetworking": true
}

[algobarb]

The changes LGTM