Add Readme in helium-admin-cli emissions folder

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In https://github.com/helium/helium-program-library/blob/master/packages/helium-admin-cli/emissions/
Add Readme with content:

Emissions

These files specify the actual current emissions not what can be emitted as per the HIP emission tables

As highlighted in HIP 77
The values present in these json files represent the amount that will be emitted per epoch given the current set of rewardable entities.
Networks with rewardable entities that do not yet exist or whom have decided to not currently accept rewards are not rewarded.

These files are required to be updated with the new emission values as new entities are able to be rewarded.

IOT startTime: 2023-04-18T00:00:00
Data transfer - 50% (any unused to POC)
POC - 30%
veHNT Stakers - 6%
Operations Fund - 7%
Oracles - 6% (Rewards NOT emitted)

IOT startTime: 2023-08-01T00:00:00
Data transfer - 51.5% (any unused to POC)
POC - 28.5%
veHNT Stakers - 6%
Operations Fund - 7%
Oracles - 6% (Rewards NOT emitted)

MOBILE startTime: 2023-04-18T00:00:00
Data transfer - 40% (any unused to POC)
POC - 20%
veHNT Stakers - 6%
Mappers - 20% (Rewards NOT emitted)
Service Providers - 10% (Rewards NOT emitted)
Oracles - 6% (Reward NOT emitted)