Mulliken example notebook changes

[AkashHiregange]

• The notebook for mulliken example has now been updated.
• Updated the read me file with added instructions on using carmm.
• made slight syntax changes to slab consistent bulk generator example.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 88.35%. Comparing base (f7a37a4) to head (d3a2910).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #165 +/- ## ======================================= Coverage 88.35% 88.35% ======================================= Files 82 82 Lines 3316 3316 ======================================= Hits 2930 2930 Misses 386 386 ``` | [Flag](https://app.codecov.io/gh/logsdail/carmm/pull/165/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Andrew+Logsdail) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/logsdail/carmm/pull/165/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Andrew+Logsdail) | `88.35% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Andrew+Logsdail#carryforward-flags-in-the-pull-request-comment) to find out more.

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