Further improvements to broadcast_techs

[tsmbland]

Description

This makes a number of changes to the broadcast_techs function and its usage, as a follow up to #585

• Renamed the function to broadcast_over_assets, which better describes its general usage

• Clarified the docstring, added example for using installed_as_year=False

• Removed calls to this function away from several functions in the quantities module (emission, consumption, maximum_production,capacity_in_use, minimum_production). It is now the responsibility of the code calling these functions to make sure the data is in the correct format. However, due to the check introduced in Xarray patch: Check array dimensions #647, any errors due to inconsistent formatting (i.e. trying to combine asset-level data with technology-level data) will be flagged, so I don't think this is any less robust. Overall, I think this makes these functions more readable, flexible (so long as the inputs are in a consistent format) and reduces the number of times conversions have to happen, as a converted technologies can be passed to multiple functions.

• The above change required some reformatting to other parts of the code, particularly the demand_share module

• Removed filter_with_template. This always just called broadcast_techs (the code beneath the first return statement was never accessed), so isn't required.

• Updated the tests in line with these changes

There are still a couple of TODOs in broadcast_over_assets, but I'm leaving these for now as they have knock on consequences for other parts of the code (particularly the adhoc solver and constraints), which I'm not yet comfortable changing.

[dalonsoa]

LGTM. The code is more readable with the use of technologies instead of a bunch of random words to define the same thing and the purpose of the broadcast function clearer 👍