Add shell completion templates and manpage template

src/templates/manpage.handlebars

@@ -0,0 +1,64 @@
+.TH {{spec.name}} 1 "{{spec.version}}" "{{spec.author}}" "{{spec.name}}"
+.SH NAME
+{{spec.name}} \- {{spec.description}}
+.SH SYNOPSIS
+\fB{{spec.name}}\fR [\fB--version\fR] [\fB--help\fR] [\fB<global-options>\fR] \fB<command>\fR [\fB<args>\fR]
+.SH DESCRIPTION
+{{spec.description}}
+{{#if spec.author}}
+.PP
+Author: {{spec.author}}
+{{/if}}
+{{#if spec.license}}
+.PP
+License: {{spec.license}}
+{{/if}}
+.SH OPTIONS
+{{#each spec.globalOptions}}
+.TP
+\fB{{#if short}}-\fR\fB{{short}}\fR, \fB{{/if}}--\fB{{name}}\fR
+{{escape description}}
+{{#if type}}
+Type: \fB{{type}}\fR{{/if}}
+{{#if required}}
+Required{{/if}}
+{{#if default}}
+Default: \fB{{defaultValue}}\fR{{/if}}
+{{/each}}
+.SH COMMANDS
+{{#each spec.commands}}
+.TP
+\fB{{name}}\fR{{#if aliases}} (alias: \fB{{aliases}}\fR){{/if}}
+{{escape description}}
+{{#if options}}
+.SS Options for '{{name}}':
+{{#each options}}
+.TP
+\fB{{#if short}}-\fR\fB{{short}}\fR, \fB{{/if}}--\fB{{name}}\fR
+{{escape description}}
+{{/each}}
+{{/if}}
+{{#if arguments}}
+.SS Arguments for '{{name}}':
+{{#each arguments}}
+.TP
+\fB{{name}}\fR
+{{escape description}}{{#if required}} (required){{/if}}{{#if variadic}} (variadic){{/if}}
+{{/each}}
+{{/if}}
+{{/each}}
+{{#if spec.examples}}
+.SH EXAMPLES
+{{#each spec.examples}}
+.TP
+\fB{{description}}\fR
+.EX
+$ {{command}}
+{{#if output}}
+{{output}}
+.EE
+{{/if}}
+{{/each}}
+{{/if}}
+.SH VERSION
+This man page was generated for \fB{{spec.name}}\fR version \fB{{spec.version}}\fR.