Eptr2

This is an interim release to fix minor points.

+ `pandas` is no longer required in time related utility functions (`util.time`)
+ `root_phrase` can be set in `EPTR2` object

This release can be considered a major release in terms of dependency simplification and making it lighter for the use of other applications.

+ `requests` library is replaced with `urllib3` library
+ `pandas` is now optional. If you do not provide `postprocess=True`, when initiating your `EPTR2` object you will directly get the response dictionary
+ `get_raw_response` is a new parameter (default: false) if you want the raw `urllib3` response.

+ 100 services covered!
+ "Ancillary services" (Yan Hizmetler) calls are added to convenience calls
+ "Number of licenses per participant type" call is added to convenience calls
+ Python version requirement is reduced to 3.9.6
+ Steps taken to reduce dependencies
+ More calls are added to help information

- Minor fixes to some functions
- Cost calculation functions update (still in beta)

- Fixed a problem with supply-demand call
- Changed parameters for bpm-orders and bpm-orders-w-avg from `date_time`to `date`. A deprecation warning is issued. Support will be removed from v0.3.0.
- Some internal fixes

- New calls (mostly from electricity reporting)
- Security update: `ssl_verify` is now True as default
- A new date format `se_date` is introduced. Some services require start date and end date as the same date. Therefore start/end date is introduced as a single date to regulate both start date and end date.
- A few internal changes for better parameter processing