feat: add config-based named_resources support (#1085)

[clumsy]

Fixes #1085

Test plan:
[x] Unit tests added

[x] Tested locally, e.g.:

[named_resources]
my_device={"cpu": 100, "gpu": 0, "memMB": 819200, "devices": {"vpc.amazonaws.com/efa": 1}}

[component:utils.sh]
h=my_device

Running
torchx run -s local_cwd utils.sh cal

Gives:

torchx 2025-06-29 22:29:34 INFO     loaded configs from /private/tmp/dynamic_device/.torchxconfig
torchx 2025-06-29 22:29:35 INFO     Tracker configurations: {}
torchx 2025-06-29 22:29:35 INFO     Log directory not set in scheduler cfg. Creating a temporary log dir that will be deleted on exit. To preserve log directory set the `log_dir` cfg option
torchx 2025-06-29 22:29:35 INFO     Log directory is: /var/folders/8b/nbn0wcb93m710myrqx8r_clh0000gq/T/torchx_ue1_qcab
local_cwd://torchx/sh-mjpvn04c5kmnfc
torchx 2025-06-29 22:29:35 INFO     Waiting for the app to finish...
sh/0      June 2025
sh/0 Su Mo Tu We Th Fr Sa
sh/0  1  2  3  4  5  6  7
sh/0  8  9 10 11 12 13 14
sh/0 15 16 17 18 19 20 21
sh/0 22 23 24 25 26 27 28
sh/0 29 30
sh/0
torchx 2025-06-29 22:29:36 INFO     Job finished: SUCCEEDED

[clumsy]

For your consideration @kiukchung , @d4l3k , @tonykao8080 , @andywag
If you're in favor of the feature - please feel free to suggest naming/formatting changes. Thanks!

[clumsy]

Could you please have a look, @kiukchung?