[feat] Combine perflogs for parameterised tests

[vkarak]

This PR provides the following:

1. The performance logs for paramterised tests using the filelog handler are combined in a single file that is named after the test's base name (i.e. the class name). This is very useful as a parameterised test is essentially the same test with differing parameters.
2. A new special log format specifier %(check_#ALL)s is added. If this is found in the log format, it will be replaced by all the loggable %(check_<attr>)s.
3. A new ignore_keys configuration parameter is added to the filelog log handler that allows users to ignore certain test attributes during logging. The builtin configuration already puts several attributes in that list in order to save space.
4. The default delimiter for the filelog output is reverted to | as the , may conflict with the logged env_vars and extra_resources. Users using the %(check_#ALL)s specifier should pay attention to the delimiter used in their format.

Todos

• Update docs
• Update the configuration schema

Closes #2591.

[codecov]

Codecov Report

Patch coverage: 91.42% and no project coverage change.

Comparison is base (a128328) 86.97% compared to head (3be4031) 86.98%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #2882   +/-   ##
========================================
  Coverage    86.97%   86.98%           
========================================
  Files           60       60           
  Lines        11596    11627   +31     
========================================
+ Hits         10086    10114   +28     
- Misses        1510     1513    +3     

Impacted Files	Coverage Δ
reframe/core/settings.py	100.00% <ø> (ø)
reframe/core/logging.py	80.80% <91.42%> (+0.52%)	⬆️

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[ekouts]

Lgtm, just some small comments.