omnitrace-avail generate config (#69)

* Config updates

- See PR #69 for details

- change type of OMNITRACE_DL_VERBOSE
- add "deprecated" category to OMNITRACE_ROCM_SMI_DEVICES
- reduce size of perfetto shared memory size hint
- deprecate OMNITRACE_OUTPUT_FILE in favor of OMNITRACE_PERFETTO_FILE
- set papi event choices
- read config file after reading command line
- fix update of OMNITRACE_DL_VERBOSE
- mark several settings as hidden
- timemory update support hidden attribute for settings
- rework get_perfetto_output_filename()
- Hide settings from not available backends

* Rework omnitrace-avail to support dumping configurations

* Overwrite query, tests, output flag

- Support using -O flag when dumping config
- Support checking before overwriting existing config
- Support --force to overwrite existing config
- Fix get_component_info not including omnitrace components
- Testing for dumping config

* Update documentation on omnitrace-avail

* Fix issue with timemory format + "/__w/"

* Update output prefix keys docs

* Rename --dump-config to --generate-config

* Hide MPI related options

- OMNITRACE_PERFETTO_COMBINE_TRACES and OMNITRACE_COLLAPSE_PROCESSES are hidden w/o MPI support

README.md

@@ -15,8 +15,26 @@ The full documentation for [omnitrace](https://github.com/AMDResearch/omnitrace)
 
 ### Omnitrace Settings
 
-`omnitrace-avail -Sd` will provide a list of all the possible omnitrace settings, their current value, and a description of the setting
-when running an instrumented binary.
+Generate an omnitrace configuration file using `omnitrace-avail -D omnitrace.cfg`. Optionally, use `omnitrace-avail -D omnitrace.cfg --all` for
+a verbose configuration file with descriptions, categories, etc. Modify the configuration file as desired, e.g. enable
+[perfetto](https://perfetto.dev/), [timemory](https://github.com/NERSC/timemory), sampling, and process-level sampling by default
+and tweak some sampling default values:
+
+```console
+# ...
+OMNITRACE_USE_PERFETTO         = true
+OMNITRACE_USE_TIMEMORY         = true
+OMNITRACE_USE_SAMPLING         = true
+OMNITRACE_USE_PROCESS_SAMPLING = true
+# ...
+OMNITRACE_SAMPLING_FREQ        = 50
+OMNITRACE_SAMPLING_CPUS        = all
+OMNITRACE_SAMPLING_GPUS        = $env:HIP_VISIBLE_DEVICES
+```
+
+Once the configuration file is adjusted to your preferences, either export the path to this file via `OMNITRACE_CONFIG_FILE=/path/to/omnitrace.cfg`
+or place this file in `${HOME}/.omnitrace.cfg` to ensure these values are always read as the default. If you wish to change any of these settings,
+you can override them via environment variables or by specifying an alternative `OMNITRACE_CONFIG_FILE`.
 
 ### Omnitrace Executable