Add hooks to compat functions

[Powersource]

Made by @cooldracula in #424 first

[github-actions]

Benchmark results

Part	Duration
Create 5000 new messages	266.84ms
Validate 5000 messages	352.88ms
Native to db format 5000 messages	78.55ms
Db to native format 5000 messages	67.63ms
Add 1000 elements	464.94ms
Add 1000 box1 msgs	730.33ms
Unbox 1000 box1 msgs first run	151.11ms
Unbox 1000 box1 msgs second run	69.11ms
Add 1000 box1 msgs	691.08ms
Query 1000 msgs first run	29.01ms
Query 1000 msgs second run	8.05ms
Add 1000 box2 msgs	1040.77ms
Unbox 1000 box2 msgs first run	245.66ms
Unbox 1000 box2 msgs second run	109.31ms
Migrate (+db1)	8589.40ms
Migrate (alone)	2801.69ms
Migrate (+db1 +db2)	5037.82ms
Migrate (+db2)	4198.15ms
Migrate continuation (+db2)	743.88ms
Memory usage without indexes	770.11 MB = 35.87 MB + etc
Initial indexing	1098.91ms
Initial indexing maxcpu=86	4012.33ms
Initial indexing compat	296.51ms
Two indexes updating concurrently	1861.16ms
Key one initial	58.74ms
Key two	0.96ms
Key one again	0.96ms
Reboot and key one again	61.49ms
Latest root posts	1134.83ms
Latest posts	8.65ms
Votes one initial	949.69ms
Votes again	0.41ms
HasRoot	850.97ms
HasRoot again	0.41ms
Author one posts	929.02ms
Author two posts	13.07ms
Dedicated author one posts	926.79ms
Dedicated author one posts again	0.42ms
DeleteFeed	4399.78ms
Maximum memory usage	854.54 MB = 63.91 MB + etc
Indexes folder size	10.01mb

[Powersource]

feeling allowed to merge this since it's technically not my PR, i'm just a reviewer ;)

[Powersource]

v8.1.0