Orders requests to support source_type for basemaps

[cholmes]

Is your feature request related to a problem? Please describe.

Right now I can create a orders request for basemaps with the CLI, but I can't use planet orders request to help me form the request. I believe the situation is similar in the Python side - no 'helper' method.

Describe the solution you'd like

planet orders request --source-type basemaps or something similar, where it works with the relevant parameters. Likely will take a more concrete design proposal for exactly how it'll work, as it's a little bit different than standard catalog orders.

Describe alternatives you've considered

Writing JSON by hand. It works, but it doesn't give the same level of convenience as the rest of the CLI/API.

Additional context

https://developers.planet.com/apis/orders/basemaps/ is our new documentation on basemaps. It'd be awesome if we could eventually upgrade those docs to be CLI or at least Python SDK calls instead of raw python requests stuff.

[joferkington]

It's also worth explicitly mentioning that v2 dropped all support for the basemaps API (v1 had full support for basemaps). Orders does not replace the basemaps API and basemaps API functionality and metadata is still needed to use basemap data (e.g. listing a time series and otherwise getting the information you need to use the orders API).

Similarly, NICFI customers cannot use the orders API for basemaps and must use the basemaps API for data download.

Orders support for basemaps in the python client is not sufficient to actually work with basemap data. This client still needs to support the basemap API for basic information.

[tbarsballe]

Duplicate of #752

[cholmes]

Duplicate of #752

This is actually different from that one - this is for the planet orders request command to include source_type as an option, the other one is for planet orders list to support source_type as an input - so you can actually see your basemaps orders.

[tbarsballe]

Ah, missed that. Reopening