Add hasDiskAccess config

[Powersource]

In ssb-tribes2-demo we currently have to patch ssb-db2 to get it to run, see ssbc/ssb-tribes2-demo#11 https://github.com/ssbc/ssb-tribes2-demo/blob/3d4425fec46894b4c0db601c312b65e9d58fe9ae/patches/ssb-db2%2B7.1.1.patch This config option should allow us to remove that patch.

I didn't add a test here but I'll make a PR in ssb-tribes2-demo where i test it

[Powersource]

tests passing locally (or they're at least not failing more than on master :p )

[Powersource]

The demo works now without the patch! ssbc/ssb-tribes2-demo#12

[github-actions]

Benchmark results

Part	Duration
Create 5000 new messages	525.14ms
Validate 5000 messages	503.46ms
Native to db format 5000 messages	136.80ms
Db to native format 5000 messages	114.10ms
Add 1000 elements	508.36ms
Add 1000 box1 msgs	1369.12ms
Unbox 1000 box1 msgs first run	259.53ms
Unbox 1000 box1 msgs second run	119.17ms
Add 1000 box1 msgs	1278.90ms
Query 1000 msgs first run	50.98ms
Query 1000 msgs second run	20.51ms
Add 1000 box2 msgs	2064.28ms
Unbox 1000 box2 msgs first run	499.30ms
Unbox 1000 box2 msgs second run	229.38ms
Migrate (+db1)	14038.92ms
Migrate (alone)	4966.18ms
Migrate (+db1 +db2)	10170.64ms
Migrate (+db2)	6711.80ms
Migrate continuation (+db2)	1323.43ms
Memory usage without indexes	778.61 MB = 42.36 MB + etc
Initial indexing	1632.20ms
Initial indexing maxcpu=86	5420.59ms
Initial indexing compat	867.44ms
Two indexes updating concurrently	2965.29ms
Key one initial	80.26ms
Key two	2.80ms
Key one again	6.12ms
Reboot and key one again	80.92ms
Latest root posts	1876.15ms
Latest posts	8.77ms
Votes one initial	1519.71ms
Votes again	0.48ms
HasRoot	1325.92ms
HasRoot again	0.36ms
Author one posts	1449.62ms
Author two posts	20.07ms
Dedicated author one posts	1485.88ms
Dedicated author one posts again	1.10ms
DeleteFeed	5748.00ms
Maximum memory usage	858.96 MB = 63.91 MB + etc
Indexes folder size	10.01mb

[staltz]

Yeah this seems okay.

[Powersource]

v7.2.0

[Powersource]

woops i think setting this to false doesn't force it to be false. but i think the only real usecase i know of is electron, and there you'd want to set it to true so no biggie

[github-actions]

Benchmark results

Part	Duration
Create 5000 new messages	334.00ms
Validate 5000 messages	464.73ms
Native to db format 5000 messages	99.79ms
Db to native format 5000 messages	96.45ms
Add 1000 elements	369.15ms
Add 1000 box1 msgs	978.68ms
Unbox 1000 box1 msgs first run	194.56ms
Unbox 1000 box1 msgs second run	95.21ms
Add 1000 box1 msgs	942.89ms
Query 1000 msgs first run	33.07ms
Query 1000 msgs second run	11.25ms
Add 1000 box2 msgs	1300.81ms
Unbox 1000 box2 msgs first run	353.54ms
Unbox 1000 box2 msgs second run	182.83ms
Migrate (+db1)	10540.18ms
Migrate (alone)	3288.94ms
Migrate (+db1 +db2)	7611.24ms
Migrate (+db2)	5249.50ms
Migrate continuation (+db2)	1020.84ms
Memory usage without indexes	764.32 MB = 42.89 MB + etc
Initial indexing	1425.78ms
Initial indexing maxcpu=86	3983.73ms
Initial indexing compat	576.31ms
Two indexes updating concurrently	2492.38ms
Key one initial	71.45ms
Key two	1.89ms
Key one again	0.82ms
Reboot and key one again	67.10ms
Latest root posts	1587.13ms
Latest posts	8.41ms
Votes one initial	1294.70ms
Votes again	0.33ms
HasRoot	1157.09ms
HasRoot again	0.55ms
Author one posts	1243.15ms
Author two posts	14.75ms
Dedicated author one posts	1255.64ms
Dedicated author one posts again	0.47ms
DeleteFeed	5330.58ms
Maximum memory usage	859.96 MB = 59.45 MB + etc
Indexes folder size	10.01mb