Fix tethering inet bugs, introduce a few new nodes and five new chapters of tutorial

[brusherru]

This PR includes a lot of things. Probably better to divide it for a few commits, but then it blocks the main goal: create five new chapters of the tutorial, that really works :)

New library:

• xod-cloud/basics, that has nodes to get a DateTime and external IP, using our httpbin API.

New nodes:

• xod/stream/parse-u32 — to parse uint32 integers and returns as 4 bytes. Without this node parsing numbers such as a POSIX time has a big inaccuracy, because of converting to Float.
• xod/stream/parse-number — actually parses a float from a string. Used in the cloud-number node.
• xod-cloud/feeds/cloud-string — get a string from a feed
• xod-cloud/feeds/cloud-number — get a number from a feed
• xod-cloud/feeds/cloud-boolean — get a boolean from a feed
• xod/datetime/from-posix — a new constructor
• xod/datetime/to-posix — a new destructor

New chapters of the tutorial:

• 013-custom-types — introduce to custom types using a datetime type
• 014-internet — introduce to tethering-inet a receiving a current DateTime
• 015-xod-cloud — introduce to XOD Cloud Feeds
• 111-internet — rotating servo using the data from feeds and tethering internet
• 112-standalone-internet — replacing tethering-inet with another internet provider node (probably should be renamed to something shorter)

[gabbapeople]

passed through the Grammarly

[evgenykochetkov]

The 015-xod-cloud example works kind of weird.

I attached a count with a watch to cloud-store's DONE output and run the simulations.
After 5 or 6 changes with the interval of about 20 seconds, the counter was incremented only once, and the feed shows only the first 3 values.

[evgenykochetkov]

When running 014-internet, it shows

for about 15 seconds, which is a bit confusing.

I think that more visual feedback is required.
Maybe something like this?

[evgenykochetkov]

It looks like xod-cloud/cloud-boolean-custom, xod-cloud/cloud-number-custom and xod-cloud/cloud-string-custom all share a large portion of implementation:

Maybe it should be abstracted into an utility node?

[nkrkv]

Hyperlink UTM’s are missing

[brusherru]

@nkrkv please, pay attention to the 111-internet, because I've changed it due to the requirement "The patch should be ready-to-go in its initial form".

[nkrkv]

Take two

[nkrkv]

🚀

I suggest one more structural change, though. Currently, if you get rid of numbers, here are chapters we get:

• internet (uses XOD Cloud)
• xod-cloud (talks about Feeds)
• internet (duplicate name)
• standalone-internet

Suggest making the difference apparent:

• 014-internet-tethering
• 015-xod-cloud-feeds
• 111-feed-messaging
• 112-standalone-internet

The H1 titles inside the chapters are better to match the filename.

Anther issue is with 014 chapter. You’re asking a user to “Place a tweak-pulse node” but it is there already. Suggest reverting the patch itself to the state whet INIT had Boot bound to it.

[nkrkv]

Woohoo