feat(validation): Add validation callback support

[TjazVracko]

Description

Adds support for settings validation.

Each setting can now have an attached validation callback.
The callback is called whenever the setting is changed, and it can reject the change by returning false.

The PR also adds tests for the new feature and updates the callbacks sample.

Closes #47

Areas of interest for the reviewer

All

Checklist

• My code follows the style guidelines as defined by IRNAS.
• I have performed a self-review of my code.
• My changes generate no new warnings.
• I added/updated source code documentation for all newly added or changed functions.
• I updated all customer-facing technical documentation.

After-review steps

• I will merge PR by myself.

[TjazVracko]

• feat(validation): Add helper macros for common validatiors #65
• feat(validation): Add validation callback support #64 👈 (View in Graphite)
• main

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[github-actions]

Coverage after merging feature/validation into main will be

24.21%

Coverage Report

File	Stmts	Branches	Funcs	Lines	Uncovered Lines
library/protocol/binary
user_settings_protocol_binary.c	83.33%	72.97%	100%	87.18%	113, 116–118, 118, 118–119, 121–124, 135–136, 173–174, 66–67, 71–72, 80
library/user_settings
user_settings.c	46.44%	28.19%	72%	60.82%	100, 107, 107, 110, 114, 131–132, 137–138, 138, 138, 138, 138–141, 141, 141, 141, 141–142, 145, 145, 168, 176–177, 177, 177, 177, 177–178, 183–184, 184, 184, 184, 184–185, 190–191, 191, 191, 191, 191–192, 197–198, 198, 198, 198, 198–199, 209–211, 218–219, 227, 233–234, 234, 234, 234, 234–235, 240–241, 241, 241, 241, 241–242, 247–248, 248, 248, 248, 248–249, 259, 259, 259, 265, 265, 265, 265, 271, 271, 271, 271, 278–279, 279, 279, 279, 279–280, 287, 287, 287, 287, 299–300, 300, 300, 300, 300–301, 306–307, 307, 307, 307, 307–308, 314, 316, 316, 316, 318–319, 319, 319, 321, 326, 326, 326, 329, 329, 329, 344, 350, 350, 360–361, 361, 361, 361, 361–362, 368–369, 369, 369, 369, 369–370, 378, 384, 384, 384, 384, 390, 390, 398, 398, 398, 398, 408–409, 409, 409, 409, 409–410, 415–416, 416, 416, 416, 416–417, 422–423, 423, 423, 423, 423–424, 433–434, 441, 443, 443, 443, 449, 451, 451, 451–452, 454, 456, 458, 458, 458, 460–461, 461, 461, 463–464, 469, 469, 469, 47, 472, 472, 472, 48, 480, 488, 488, 488, 496, 499, 506, 509, 516, 52, 523, 523, 523–524, 524, 524–525, 527, 53, 530, 533, 535, 535, 535, 537–538, 538, 538, 540, 545, 548, 555–556, 562, 565, 567, 567, 567, 569–570, 570, 570, 572, 577, 577, 577, 58, 580, 580, 580, 587, 59, 59, 59, 59, 59, 592, 594, 594, 594, 596–597, 597, 597, 599, 60, 600, 604, 607, 61, 612, 614, 614, 614, 616–617, 617, 617, 619, 62, 62, 62, 62, 62, 620, 623, 623, 623, 626, 626, 626, 632, 634, 634, 634, 636–637, 637, 637, 639, 64, 643, 645, 645, 645, 647–648, 648, 648, 650, 653, 655, 655, 655, 657–658, 658, 658, 660, 663, 665, 665, 665, 667–668, 668, 668, 670, 675, 675, 675, 678, 678, 678, 685, 685, 685, 688, 688, 688, 693, 695, 695, 695, 697–698, 698, 698, 700, 705, 705, 705, 708, 708, 708, 715, 718, 725, 725, 725, 728, 728, 728, 769, 771, 771, 771, 773–774, 774, 774, 776–777, 779, 781, 781, 781, 783–784, 784, 784, 786–787, 791, 791, 791, 794, 794, 794, 801, 801, 801, 804, 804, 804, 811, 83–84, 88–89, 94–95, 95, 95, 95, 95–98, 98, 98, 98, 98
user_settings_json.c	45.99%	34.75%	100%	52.44%	100–101, 103, 106, 114, 127–128, 128, 128, 128, 128–129, 133–134, 143–144, 160, 160, 160, 160, 160, 160, 160, 160, 162, 165, 169–171, 173–175, 181–183, 185–187, 189–191, 193–195, 197–199, 216–217, 217, 217, 217, 217, 221–222, 222, 222,

[MarkoSagadin]

Two nits:

• the parsed from user could be parsed from user input
• In doxygen for the user_settings_set_validate_cb_with_id you could completely remove the third paragraph (about the asserts), the doxygen for the user_settings_set_validate_cb_with_key should then be written in a more generic manner (eg. user_settings_exists_with_key -> user_settings_exists_with_*)

[MarkoSagadin]

Another nit:

• validate could be changed to validator, so verb to noun change, it makes a bit more sense to me, but in any case it is clear what this does.

[MarkoSagadin]

[Re: lines +78 to +90]

Nit: wouldn't be enough to just memset to zero the struct (as it is already done) and then just set non-zero values? Below should be enough:

	struct user_setting *us = mem;
	memset(us, 0, sizeof(struct user_setting));
	us->id = id;
	us->key = (char *)key;
	us->type = type;
	us->max_size = size;
```<!--__GRAPHITE_HTML_TAG_START__--><span class='graphite__hidden'><br/><br/>See this comment inline on <a href="https://app.graphite.dev/github/pr/IRNAS/irnas-usersettings-lib/64?utm_source=unchanged-line-comment">Graphite</a>.</span>

<!--__GRAPHITE_HTML_TAG_END__-->

[TjazVracko]

Yup.

Blame past me :D

[MarkoSagadin]

:D