``v7`` breaking changes megathread

[fselmo]

Main thread for tracking breaking changes slated for the next major version release of web3.py - v7. This will be an evolving issue much like #1416 was for v6.

Candidates:

### Tasks
- [ ] https://github.com/ethereum/web3.py/issues/3105
- [ ] https://github.com/ethereum/web3.py/issues/3095
- [ ] https://github.com/ethereum/web3.py/issues/3210
- [ ] https://github.com/ethereum/web3.py/issues/3085
- [ ] https://github.com/ethereum/web3.py/issues/2844
- [ ] https://github.com/ethereum/web3.py/issues/3119
- [ ] https://github.com/ethereum/web3.py/issues/3241
- [ ] https://github.com/ethereum/web3.py/issues/3239
- [ ] https://github.com/ethereum/web3.py/issues/3240
- [ ] https://github.com/ethereum/web3.py/issues/715
- [ ] #2816
- [ ] #2685
- [ ] https://github.com/ethereum/web3.py/issues/3108
- [ ] https://github.com/ethereum/web3.py/issues/901
- [ ] https://github.com/ethereum/web3.py/issues/3175
- [ ] https://github.com/ethereum/web3.py/pull/2964
- [ ] https://github.com/ethereum/web3.py/issues/3188
- [ ] https://github.com/ethereum/web3.py/issues/3164
- [ ] https://github.com/ethereum/web3.py/issues/3032
- [ ] #2884
- [ ] https://github.com/ethereum/web3.py/issues/2995
- [ ] https://github.com/ethereum/web3.py/issues/3021
- [ ] https://github.com/ethereum/web3.py/issues/2990

[kclowes]

Return ipc path even if it doesn't yet exist. See #2911

[pacrob]

Remove the ethPM module, deprecated in #2953

[kclowes]

#2964 - Change provider User-Agent header to be more readable.

[kclowes]

Better UX for provider-specific middlewares. See: #2770

edit: issue created (#2990)

[reedsa]

Remove the miner API, deprecated in #2856.

[pacrob]

Here, then upstream libs:

• Remove python 3.7 support
• Branch name change: master -> main

[pacrob]

AttributeDict updates #3105

[pacrob]

web3 v7 should set hexbytes>=1.0.0.

Bottom pins for our other libs should move up to at least the release that dropped py37 support

[kclowes]

Where possible, have all errors thrown inherit from Web3Exception, or ENSException. See #1864.