[FEATURE] Add Custom Template Support

[DFanso]

Allow users to define their own commit message templates:

commit llm template --set

[suraj-mandal]

Hi, I would like to work on this issue, if no one is picking this one up!

[DFanso]

sure @suraj-mandal

[suraj-mandal]

Sure, having a look at this. There is festival here right now. But I am picking it up by monday IST hours.

[DFanso]

sure no problem. enjoy

[aqsaaqeel]

Hey, @suraj-mandal are you working on this? if not, @DFanso can you assign it to me?

[suraj-mandal]

Yes I am working on this.. give me a couple of days.. then you pick this up

[DFanso]

hey @suraj-mandal are you still working on this

[suraj-mandal]

Yes. I will finish by this weekend. If not, someone else can pick this up

[aqsaaqeel]

I can take it up @suraj-mandal